Photo by Antoine Dautry on Unsplash
While it is true that you are allowed to bring your calculator to your IGCSE Mathematics exams, you do not want to rely on it for your whole test. There are two reasons for this. One: you will waste time plugging in numbers – and the exams are too long for you to waste time – and two: in the unlikely event of your calculator breaking/running out of battery during the exam, you want to be able to solve some questions by yourself.
It’s always handy to have good mental maths skills, but some students are not comfortable with the methods they learn at school. Luckily, there are alternative methods to help you out. Some may be confusing at first, but we recommend you try them out by yourself so you understand how they work. Hopefully they will help you!
Long Division – The Box Method
Some students struggle with long division without a calculator, but this method makes it look easy. The process involves breaking down the numbers to make the division easier. Here’s a video explaining the whole process:
If you have trouble finding out which number you can divide another number by, there are a few tricks you can memorise. Divide by:
- 10 if the number ends in 0
- 9 when the digits are added together and the total is evenly divisible by 9
- 8 if the last three digits are evenly divisible by 8 or are 000
- 6 if it is an even number and when the digits are added together the answer is evenly divisible by 3
- 5 if it ends in a 0 or 5
- 4 if it ends in 00 or a two digit number that is evenly divisible by 4
- 3 when the digits are added together and the result is evenly divisible by the number 3
- 2 if it ends in 0, 2, 4, 6, or 8
Long Multiplication – Line Method
An interesting alternative multiplication method is the Line Method, which is said to have originated from Japan. It is quite simple and involves drawing lines intersecting each other. This video shows clearly how it is done:
Long Multiplication – Base Method
Alternatively, you could use this Vedic maths method to do long multiplications quickly. Te method revolves around using multiples of ten. It seems complicated at first and is quite difficult to explain, so watch this video to get a better understanding of it.
Of course, there are other methods out there and you could always stick to the ones you already know. The important thing is to get loads of practice so you are less dependent on your calculator.