L1 · Order of Operations: x and / Before + and -

Learning goal

“I can find the value of an expression by doing multiplication and division first, then addition and subtraction, working from left to right inside each pair.”

Expression — a mathematical phrase built from numbers and operations, with NO equals sign (e.g. 5 + 3 x 4). It names a value.

Value — the number an expression works out to when you calculate it.

Order of operations — the agreed order everyone follows so an expression has only one value: x and / before + and -, left to right inside each pair.

Worked example

Find the value of 5 + 3 x 4. Step 1: Scan the expression. It has a + and a x. The order of operations says x and / are done BEFORE + and -. Step 2: Do the multiplication first: 3 x 4 = 12. The expression becomes 5 + 12. Step 3: Now add: 5 + 12 = 17. The value is 17. Warning, said plainly: a student who just marches left to right gets 5 + 3 = 8, then 8 x 4 = 32. That is a different answer - and it is wrong, because the x had a turn before the +. One expression must have one value, and the rule is what guarantees it.

Check yourself — explain it

In 5 + 3 x 4, why do we multiply before we add?

Paired problem — example still visible

Find the value of 2 x 6 + 5 -> 17 (2 x 6 = 12 first, then 12 + 5 = 17)

Faded completion — last step is yours

"20 - 8 / 4: first do 8 / 4 = ___; then 20 - 2 = 18" -> 2

Ready to practise?

10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.

Start practice →Take the unit quiz