Calculate the difference in different contexts | Exit Quiz | Oak National Academy

When would we be best to use the ‘counting on’ strategy to find the difference?

• When the numbers are close together.

• When the numbers are far apart.

• If we cannot work out the answer.

Answer explanation

We use the ‘counting on’ strategy to find the difference between numbers that are close together, for example 6 and 8 are close together, so we could use a ‘counting on’ strategy.

If a book costs £4 and a toy car costs £12, how would we efficiently calculate the difference in price?

• Subtract £4 from £12

• Count on from £4 to £12

• Add £4 and £12

Answer explanation

To find the difference between £4 and £12, we would subtract £4 from £12, bridging 10 These amounts are far apart, so starting at £4 and ‘counting on’ would not be the most efficient strategy.

A teddy costs £9 and a toy car costs £12, how would we calculate the difference in price?

• Subtract £9 from £12

• Count on from £9 to £12

• Add £9 and £12

Answer explanation

We use the ‘counting on’ strategy when numbers are close together. 9 and 12 are close together, so we could ‘count on’ from £9 to £12

It takes Sofia 4 minutes to walk to school. It takes Jun 12 minutes to walk to school. How much longer does it take Jun to walk to school than Sofia? ___ minutes.

Answer explanation

12 - 4 = 8, so the difference between 4 and 12 is 8 It takes Jun 8 more minutes to walk to school than Sofia.

Jacob wants to buy a new pencil case that costs £12 and he has saved £9 so far. How much more money does Jacob need to save? £___

Answer explanation

12 - 9 = 3 The difference between 12 and 9 is 3, so Jacob needs to save £3 more to buy the pencil case.

When playing a game, the difference between Izzy’s score and Lucas’ score is 3, Izzy scored 9 so how many points could Lucas have scored?

Answer explanation

3 more than 9 is 12, and 3 less than 9 is 6, so Lucas could have scored 12 or 6 points.