📖Definition
This module covers a variety of calculations involving +, -, x, ÷ and a few percentages. Most importantly you need to be aware of BODMAS as this crops up in many places.
BODMAS
BODMAS stands for:
Brackets
Other (squaring, roots, other exponents)
Division
Multiplication
Addition
Subtraction
and shows the order in which operations must be done when working out sums with more than one operation
💡Tips/hints
It often helps to add brackets round the parts of a calculation that must be done before the others.
Then, do everything in the brackets before any of the other operations.
Sometimes there's a short cut to making a calculation easier.
For example, if you're asked to calculate 3 x 97 + 7 x 97, you could work out 3 x 97 and then 7 x 97 and add the two answers.
A quicker way is to see that both 3 and 7 are multiplied by 97 so we've got (3 + 7) x 97 ie. 10 x 97 = 970.
Also, if you're adding or subtracting a number that's close to a much rounder figure, do the sum with the rounder figure and then make the adjustment.
For example, a farmer has 314 sheep. She sells 197 at market. How many does she have left?
197 is just 3 less than 200. So, take 200 from 314 to get 114. Now add the 3 back on to get 117.
✏️Example
Calculate ( 3 + 5 ) x 4 - 6 ÷ 3 + 7
✅Solution
Using BODMAS, the part that needs to be done first is in the Brackets so the calculation becomes
8 x 4 - 6 ÷ 3 + 7
Now it will help to put some brackets around those steps that need to be worked out before the others
in this case Division and Multiplication. So, the calculation becomes
( 8 x 4 ) - ( 6 ÷ 3 ) + 7 = 32 - 2 + 7 = 37.