Order of operations

For grown-ups: this lesson in words

Year 6 · Maths

Order of operations: I can work out a calculation in the right order: brackets first, then × and ÷, then + and −.

1. Sam has 2 apples and 3 bags, with 4 apples in each bag.

   3 bags of 4 is 3 × 4 = 12 apples. We work out the bags first.

   2 + 12 = 14

   2 + 3 × 4 = 14

   Picture: Sam's: 2 apples, bag: 4 apples, bag: 4 apples and bag: 4 apples. The groups are pushed together and counted. 14 apples altogether.

2. There is a rule for the order we work things out. Three boxes: first, next, last.

   Brackets ( ) come first.

   Next come × and ÷: multiplying and dividing.

   Last come + and −: adding and subtracting.

   Picture: Sorting into 3 groups: First, Next, Last. First: ( ) brackets (number sign). Next: × and ÷ (number sign). Last: + and − (number sign).

3. Your turn: Here are 7 pears, and 2 bags with 5 pears in each bag. 7 + 2 × 5 = ?

   Picture: 7 pears, bag: 5 pears and bag: 5 pears.

   Choose one:

   • 14
   • 17
   • 45

   Answer

   The answer: 17

   2 × 5 = 10 first. Then 7 + 10 = 17.

   Picture: 7 pears, bag: 5 pears and bag: 5 pears. The groups are pushed together and counted. 17 pears altogether.

Words to know

brackets:

The curved marks ( ) round part of a calculation. Work out that part first.

operation:

Adding, subtracting, multiplying or dividing.

order of operations:

The rule that says which part of a calculation to work out first.