When two signs tie, take the left one

A chit — a small bill — says 24 ÷ 4 × 2. One order gives 12. The other gives 3.

The rule

× and ÷ are on the same level. So are + and −. Signs on one level have the same rank.

With two signs on one level, the signs cannot decide. Do the left one first. That is the agreed rule.

For 24 ÷ 4 × 2, first 24 ÷ 4 = 6. Then 6 × 2 = 12.

The same is true for + and −. In 50 − 20 + 5, first 50 − 20 = 30. Then 30 + 5 = 35.

Try the lab to finish this lesson.