MMI Calculation Questions: The Ultimate MMI Interview Guide

Many students shudder at the thought of a drug MMI calculation station turning up in their upcoming medical school interview. MMI Drug Calculation questions can be very tricky. Whether you are a maths mogul or need a bit of help, this article is for you!

Calculation skills are required not just for your interview, but throughout your degree and on the job as a doctor!

Stick with us and we’ll walk you through step-by-step how to ace your MMI interview calculation scenario, as well as how to gain confidence with numbers, manage your time in the station and familiarise yourself with the common MMI Maths stations.

Do you need a bit more MMI interview practice? Our experts are here for you! Book into one of our mock interviews, or 1:1 interview preparation today.

👉🏻 Read more: Ultimate Medicine Interview Preparation Guide

What Are MMI Calculation Questions? (Medicine, Dentistry & Pharmacy)

Calculation stations are an increasingly common MMI interview station at UK Medical Schools. You might also face calculation problems in a separate numeracy test, such as that set by Keele University.

In these stations, students are presented with some basic clinical calculations, at the ability expected of someone who has passed their GCSE maths and UCAT. Most universities will not provide a calculator, therefore, these stations test several skills:

1. Your ability to perform calculations under time pressure
2. Mental arithmetic skills
3. Understanding of drug dosing and interpretation of formulae

Questions will be presented to you within the context of a clinical scenario, and it will be your job to filter information, recognise relevant information to the question and complete the calculation correctly.

👉🏻 Read more: 7 Tips to Ace Your MMI Medical School Interview

Which Medical & Dental Schools Have MMI Calculation Stations?

Many medical and dental schools include calculation stations in their interview. Here are what a few say about them:

Sunderland Numeracy Test

Sunderland Medical School introduced a numeracy test which is completed before their medicine interview. This test plays a pivotal role in evaluating candidates before they progress to the interview stage.

This is what Sunderland say about their test:

“The numeracy test is now part of the interview selection process and consists of a 40-minute online test that contains approximately 20 questions with some having multiple sections.

The level of numeracy required for the test is that for GCSE maths and if an equation is required that will be supplied as part of the question; this could be a BMI or similar calculation.”

Birmingham Medical School MMI Calculation Stations

Birmingham Medical School have a calculation station in their MMI Interview. This is what they say about it:

“You will be asked to undertake simple mathematical calculations involving data interpretation that has clinical relevance. The mathematical skills that are being tested are at or below GCSE level, and those taking A-level Mathematics are not necessarily at an advantage.

The sophistication of each task is to recognise which piece or pieces of data need to be manipulated at a particular stage and to determine the precise logical and mathematical approach that needs to be applied. There will be several stages in the calculations, and to establish the order in which these are performed is important, too.”

To prepare effectively for these MMI calculation stations, engage in regular practice that emphasises not just the execution of calculations but also the development of a strategic approach to problem-solving.

Additionally, consider working with sample questions or participating in mock MMI sessions. This type of preparation can provide valuable experience in managing time effectively, working under pressure, and ensuring precision in your calculations - all key elements for success in Birmingham Medical School's MMI calculation stations.

MMI Drug Calculation Questions: Common Types of Questions

Question Type 1: Dosage Calculations

Drug dosage calculations are the most likely calculation stations you will face in your MMI interview.

In this station, you’ll be given the dosage of a medication. This can be given relative to time, body weight, age or other clinical factors.

MMI Dosage Calculation Worked Question & Answer

A 53-year-old man has a serious infection. He currently weighs 92kg and has a blood pressure of 130/79. An antibiotic is dosed at 20mg/kg/h. How many mg of antibiotic will the patient receive in 4 hours?

In approaching this MMI calculation question, it's crucial to identify the key information and understand how it relates to the calculation required. Let’s break down the process:

1. Identify Relevant Information: The most critical information in this scenario is the patient's weight and the dosing information of the antibiotic. Other details like age or blood pressure, while important clinically, are not directly relevant to this calculation.
2. Understand the Dosing Formula: The antibiotic is dosed at 20 mg per kilogram per hour. This means for each kilogram the patient weighs, they should receive 20 mg of the antibiotic every hour.
3. Simplify the Calculation: Focus on one step at a time. First, calculate the dose for one hour. The patient weighs 92 kg, so multiply this by the 20 mg/kg dosing rate. 92x20 = 1840mg in 1h. This step is crucial as it sets the foundation for the next part of the question.
4. Extend the Calculation Over the Required Time: The question asks for the total dosage over 4 hours. Having calculated the hourly dose, you simply multiply this by 4. 4x1840 = 7360mg
5. Recheck and Confirm: Finally, it's always a good idea to recheck your calculations. This not only ensures accuracy but also demonstrates to the interviewer that you are thorough and meticulous in your approach.

Top Tip: These questions are often written in the order of information that you need to process. Start with the first sentence and do the calculations needed then move to the second sentence!

Question Type 2: Concentration, Volume and Mass MMI Interview Questions

These questions are slightly more complex and require the use of the concentration, volume and mass formula, which you should be familiar with from GCSE maths.

As a recap, the formula triangle, or word formula can be used, whichever your preference is. Units are calculated in the same way. For instance, if mass is measured in grams, volume is measured in mL, the concentration will be measured in g/mL.

Top Tip: Volume was commonly measured in cm3 at GCSE, whereas volumes in medicine are mostly measured in mL. 1mL = 1cm3.

Let’s go through an example:

Volume/Concentration Calculation Worked Question & Answer

A 65-year-old female has a history of hypertension. She is prescribed a medication with a concentration of 5 mg/mL to be administered intravenously. Based on the patient’s weight, her calculated dose is 14mg. Calculate the volume of medication to be drawn into a syringe for a single dose.

To solve this MMI dose concentration question, the first step will be identifying the relevant information:

• The medication concentration is 5 mg/mL.
• The prescribed dose of medication is 14mg.
• To calculate the volume, we’ll use the equation volume = mass/concentration
• Volume = 14 mg / 5 mg/mL = 2.8 mL
• Therefore the patient should receive a volume of 2.8ml.

Top Tip: You must practice these questions, and become quick at working out the formulae that you need to help.

Question Type 3: Percentage Concentration MMI Stations

In medication concentration percentage calculations, you will be given a percentage concentration, rather than a concentration in units like mg/mL which you are used to. With this percentage, you need to be able to calculate the mass or volume of the drug given.

The most important thing to know for these questions is the convention that 1% concentration means that there is 1g of drug in every 100 mL.

In shorthand, 1% = 1g/100mL = 0.01g/mL

Let’s have a look at this in a question:

Percentage Concentration Calculation Worked Question & Answer

A patient requires 10g of a medication, which comes as a 5% solution in 1L bags. What volume will the patient need to be administered to receive a 10g dose?

• From convention, we know that a 5% solution means that there is 5g in every 100mL.
• Therefore in a 1L bag, there will be 50g of the medication.
• For the patient to be administered 10g, they will need 1/5th of the solution.
• ⅕ x 1000mL = 200 mL

Therefore the patient should be given 200mL of the solution to receive the dose they require.

Top Tip: This is a common scenario that doctors and nurses encounter at work - so they are quite common at MMI interviews. You must practice them!

👉🏻 Read more: Medicine Interview Questions & Answers Guide

Question Type 4: Unit Conversion MMI Interview Calculation Questions

The below table has a useful summary of the most common units you’ll need to be comfortable converting between in your calculation MMI station.

So how will these questions be presented? Have a look at the below example.

Unit Conversion Worked Question & Answer

A 100kg patient is given a fluid infusion at a rate of 30ml/kg/day. The doctor wants to know the fluid infusion rate in litres per hour. Calculate this and give your answer in the units L/hour

To answer this question, we need to compare what units we are starting with, and what units we want.

We start with ml/kg/day and want to end with L/hour.

• Let’s handle the kg part first:
• We know the rate of infusion is 30ml per kg in a day, and we know the patient weighs 100kg
• Therefore in a day they will receive, 30ml x 100kg = 3000mL
• Let’s rewrite this - 3000mL/day
• Now we need to convert mL to L, by dividing by 1000
• Now we have a 3L/day fluid infusion rate
• The final step is converting the rate in 1 day, to the rate in 1 hour.
• 1 day contains 24 hours, so to calculate the hourly rate, we need to divide by 24
• Therefore the rate of fluid infusion is 3/24 = 0.125L/hour

Top Tip: Always check the units of the question so you know if you are working in milliltres or litres!

Question Type 5: IV Drip Rate Questions

For these questions, you will be presented with an unfamiliar term - the “drop factor”. From its units (drops/mL), you should be able to decipher that the drop factor describes the number of drops of fluid which total the volume of 1mL.

For instance, drop factor = 15, means that there are 15 drops in 1mL of IV fluid.

Let’s see this in context:

IV Drip Rate Worked Question & Answer

Key MMI Calculation Formulas To Memorise

It helps to have a small set of formulas ready so you are not deriving them under pressure. Weight-based dose = patient weight (kg) x dose per kg. Volume to draw up = mass (mg) / concentration (mg/mL). Percentage solution: a 1% solution = 1 g in 100 mL = 0.01 g/mL.

IV infusion rate (mL/hour) = total volume (mL) / time (hours). IV drip rate (drops/min) = (volume in mL x drop factor in drops/mL) / time in minutes. Unit conversions: x1000 from mg to mcg, divide by 1000 from mL to L. Always finish by checking your answer is in the units the question asked for.

A patient is prescribed an IV antibiotic. They require 600mL of antibiotic solution to be given, and the doctor asks that this be delivered over 2 hours. The drop factor is 12 (12 drops in 1mL). Calculate the IV Drip rate in drops/minute.

This question can seem daunting due to the new terminology, but it involves the same calculation principles that we have practised!

• The patient requires an IV infusion rate of 600ml in 2 hours, this simplifies to 300ml/hour.
• Now, let’s convert per hour to per minute
• Remember that LESS fluid will be delivered per minute than per hour, so we need to divide by 60.
• 300 / 60 = 5mL/min
• However, the answer we want is in drops per minute
• We know that there are 12 drops in 1mL, therefore in 5mL, there will be 60 drops.
• Hence, the answer is 60 drops/min

👉🏻 Read more: 280 Medical School MMI Interview Questions

Interviewer Perspective: What MMI Examiners Look for in Calculation Stations

When it comes to MMI (Multiple Mini Interview) calculation stations, interviewers are looking for more than just the ability to perform accurate calculations. Here are key insights from MMI examiners on what they assess:

1. Accuracy and Precision: First and foremost, examiners evaluate the accuracy of the calculations. They expect candidates to arrive at the correct answer using appropriate methods.
2. Problem-Solving Approach: Interviewers observe the problem-solving approach of candidates. They look for logical and systematic methods, rather than haphazard guessing or jumping to conclusions without proper analysis. If it's written - always show your working out on the page!
3. Time Management: Given the time constraints of MMI stations, efficient time management is crucial. Examiners may notice how candidates balance speed with accuracy.
4. Stress Management: The ability to remain calm and composed under pressure is a key trait of being a doctor or dentist. Examiners observe how candidates handle the stress of complex calculations within a limited timeframe amidst the noise of the MMI room.
5. Error Checking: It can be quite stressful in the MMI interviews - it is important that you check your answers to avoid silly mistakes.

In summary, MMI calculation stations are not just about the numbers. They are designed to assess a range of skills including analytical thinking, clinical understanding, communication, and the ability to work under pressure – all essential qualities for a future medical professional.

MMI Maths Questions: How To Handle Time Pressure In The Calculation Station

Time pressure is usually the main reason why students struggle in the Multiple Mini Interview Calculation Stations. Remember that the difficulty of questions is proportional to the time you’ve been given to solve them.

To maximise your efficiency in this station, we recommend you follow these steps:

1. Read the last line of the question to see what you’ve been asked to do.
2. Skim-read the rest of the question, jotting down key numbers including units.
3. Re-read the last line of the question to check your understanding of what the question is asking you to do.
4. Complete the calculation.
5. Check the units of your answer match those the question has asked for.

Another way you can reduce the time pressure in the MMI station is by optimising your mental maths skills through daily practice.

👉🏻 Read more: NHS Hot Topics in Medicine 2024

MMI Numeracy Questions: Practice Questions & Answers

Here you will find some Interview MMI Calculation Station example questions and answers. This section is designed to help medical, dental, veterinary and nursing school applicants practice and refine their numerical skills, which are vital for success in MMI interviews.

These examples cover a range of topics, from drug dosages to infusion rates, providing a realistic glimpse into the calculations you'll encounter in the medical field. Whether you're prepping for an interview or honing your medical math skills, these questions and answers are tailored to support your learning journey.

Interview Calculation Questions

1. A patient's medication dosage is prescribed as 0.1 mg per pound of body weight. If the patient weighs 180 pounds, how many milligrams of medication should they receive?
2. A child is prescribed medication at a dose of 15 mg/kg/day, divided into 3 doses. If the child weighs 30 kg, how much medication should they receive per dose?
3. A patient needs an IV infusion of a drug at a rate of 80 mg per hour. The medication is available in a concentration of 400 mg per 500 mL. What should be the infusion rate in mL per hour?
4. A doctor prescribes 500 mg of a medication, and the tablets available are 250 mg each. How many tablets should the patient take?
5. A medication is provided as a 0.5% w/v solution. If a dose of 2 grams is needed, what volume of the solution should be administered?
6. A patient weighing 165 pounds is prescribed a drug at 2 mg/kg. How many milligrams of the drug should be administered?
7. An IV drip is set to deliver 20 mL/kg/day of fluid. If a patient weighs 60 kg, how many mL of fluid should they receive in 24 hours?
8. A medication dose is 5 mg per kilogram of body weight, administered twice daily. For a patient weighing 55 kg, what is the total daily dosage in milligrams?
9. An infant is prescribed a medication at a dose of 10 mg/kg. If the infant weighs 8 kg, how many milligrams of medication should be administered?
10. A patient needs an IV infusion of 1000 mL over 12 hours. What should be the infusion rate in mL per hour?
11. A medication is available as 200 mg tablets. A patient is prescribed a dose of 800 mg. How many tablets should the patient take?
12. A patient requires medication at a dose of 20 mg/kg, to be given in two divided doses per day. If the patient weighs 70 kg, what is the dose per administration?
13. A patient requires a dose of 500 mg of a medication that comes in 100 mg tablets. How many tablets should be administered?
14. A medication is supplied as a 1% solution, and a patient requires a dose of 250 mg. Calculate the necessary volume in mL to be administered.
15. A patient's weight is 75 kg, and they require a drug at a dose of 1 mg/kg every 6 hours. How many milligrams should they receive per dose?
16. A medication's recommended dosage is 0.2 mg per pound of body weight, administered once daily. If a patient weighs 150 pounds, what is the correct dosage in milligrams?
17. An IV bag contains 500 mL of fluid to be administered over 8 hours. What should be the infusion rate in mL per hour?

Answers to Interview MMI Calculation Stations

1. 18 mg (0.1 mg/lb * 180 lbs)
2. 150 mg per dose (15 mg/kg/day / 3 doses * 30 kg)
3. 100 mL/hour (80 mg/hour / 400 mg * 500 mL)
4. 2 tablets (500 mg / 250 mg per tablet)
5. 400 mL (2 g / 0.5%)
6. 150 mg (165 lbs / 2.205 lbs/kg * 2 mg/kg)
7. 1200 mL/day (20 mL/kg/day * 60 kg)
8. 550 mg per day (5 mg/kg * 55 kg * 2 doses)
9. 80 mg (10 mg/kg * 8 kg)
10. 83.33 mL/hour (1000 mL / 12 hours)
11. 4 tablets (800 mg / 200 mg per tablet)
12. 700 mg per dose (20 mg/kg * 70 kg / 2 doses)
13. 5 tablets (500 mg / 100 mg per tablet)
14. 25 mL (250 mg / 1%)
15. 75 mg (1 mg/kg * 75 kg)
16. 30 mg (0.2 mg/lb * 150 lbs)
17. 62.5 mL/hour (500 mL / 8 hours)

👉🏻 Read more: Preparation for MMI Medicine Interviews