Choose the best mental math strategy for the given problem.

Which mental math strategy helps you solve 8 + 5 by thinking (8 + 2) + 3?

Choose the best mental math strategy for the given problem.

To mentally add 34 + 9, which strategy is most efficient?

Choose the best mental math strategy for the given problem.

What is the ‘make a ten’ strategy used for 7 + 6?

Choose the best mental math strategy for the given problem.

When you solve 15 – 8 mentally by thinking 15 – 5 – 3, what strategy are you using?

Choose the best mental math strategy for the given problem.

Which method is an example of the ‘near doubles’ strategy for 6 + 7?

Choose the best mental math strategy for the given problem.

If you want to solve 23 + 19 mentally, which compensation strategy would you use?

Choose the best mental math strategy for the given problem.

What is the mental math strategy for 42 – 7 by thinking 42 – 2 – 5?

Choose the best mental math strategy for the given problem.

To find 50 + 35 mentally, which partitioning strategy is most direct?

Choose the best mental math strategy for the given problem.

Which is an example of the ‘near doubles’ strategy for 8 + 9?

Choose the best mental math strategy for the given problem.

Mentally subtracting 7 from 45 using the ‘counting on’ strategy would start from what number?

State whether the following statement is True or False.

Counting on is a mental math strategy primarily used for addition.

State whether the following statement is True or False.

When you ‘make a ten’, you always add 10 to a number.

State whether the following statement is True or False.

The ‘compensation’ strategy involves adjusting a number to make calculations easier.

State whether the following statement is True or False.

To find 12 – 3 mentally, you can count back three from 12.

State whether the following statement is True or False.

Near doubles’ means you double a number and then make a small adjustment.

State whether the following statement is True or False.

Mentally adding 19 is the same as adding 20 and then subtracting 1.

State whether the following statement is True or False.

The ‘breaking apart’ strategy works only for addition, not subtraction.

State whether the following statement is True or False.

To solve 25 + 7 mentally, you can think 25 + 5 + 2. This is using ‘bridging through ten’.

State whether the following statement is True or False.

Mental math is about solving problems quickly without using paper or a calculator.

State whether the following statement is True or False.

Fact families’ are not useful for mental math strategies.

Choose the correct True/False statement with its reason.

Statement: To mentally add 48 + 5, you can think 48 + 2 + 3. Reason: This is using the ‘making a ten’ strategy.

Choose the correct True/False statement with its reason.

Statement: Subtracting 9 from a number mentally is best done by counting back 9. Reason: Counting back is always the fastest method.

Choose the correct True/False statement with its reason.

Statement: When adding 7 + 8 mentally, using (7 + 7) + 1 is called ‘near doubles’. Reason: You are doubling one number and adjusting.

Choose the correct True/False statement with its reason.

Statement: To mentally solve 36 + 18, you can add 36 + 20 and then subtract 2. Reason: This is an example of the ‘compensation’ strategy.

Choose the correct True/False statement with its reason.

Statement: You can mentally find 63 – 5 by thinking 63 – 3 – 2. Reason: This uses the ‘breaking apart the subtrahend’ strategy to reach a friendly ‘ten’.

Choose the correct True/False statement with its reason.

Statement: The strategy ‘counting on’ is only for subtraction. Reason: You count backwards when subtracting.

Choose the correct True/False statement with its reason.

Statement: To quickly add 25 + 25 mentally, you use the ‘doubles’ strategy. Reason: You are adding two identical numbers.

Choose the correct True/False statement with its reason.

Statement: When you ‘partition’ a number like 45, you can break it into 40 + 5. Reason: This makes it easier to add or subtract ‘tens’ and ‘ones’ separately.

Choose the correct True/False statement with its reason.

Statement: Using ‘known facts’ like 6 + 4 = 10 helps with mental math. Reason: These basic facts are the building blocks for solving more complex problems.

Choose the correct True/False statement with its reason.

Statement: To mentally subtract 3 from 50, you should think 50 – 10 + 7. Reason: This is a correct application of the ‘compensation’ strategy.

Select an item from Column A, then select its match in Column B.

Fill in the blank with the correct word or phrase.

To solve 16 + 5 mentally, you can use the ‘make a ten’ strategy by thinking (16 + 4) + — Select —5101counting onten3known factspartitioningcompensationnear doubles.

Fill in the blank with the correct word or phrase.

When you add 20 to a number and then subtract 1, you are using the — Select —known factsnear doubles1partitioningcompensationcounting onten3105 strategy.

Fill in the blank with the correct word or phrase.

To mentally subtract 7 from 34, you can break apart 7 into 4 and — Select —53ten1compensationpartitioningknown factsnear doubles10counting on, so 34 – 4 – 3.

Fill in the blank with the correct word or phrase.

The strategy of doubling a known fact like 7 + 7 = 14 and then adding or subtracting 1 for 7 + 8 is called ‘— Select —partitioning1near doublestencounting on310known facts5compensation‘.

Fill in the blank with the correct word or phrase.

Mentally adding 23 + 45 can be done by partitioning: (20 + 40) + (3 + — Select —1partitioningnear doublesten35known facts10compensationcounting on).

Fill in the blank with the correct word or phrase.

When you count up from the smaller number to the larger number to find the difference, you are using the ‘— Select —tennear doublespartitioningcounting on101known facts35compensation‘ strategy for subtraction.

Fill in the blank with the correct word or phrase.

Knowing that 10 – 3 = 7 is an example of using — Select —counting onnear doublespartitioning15compensationknown factsten103 in mental math.

Fill in the blank with the correct word or phrase.

To add a number ending in 9, like 35 + 9, you can add — Select —3counting oncompensation5known facts1near doubles10partitioningten and then subtract 1.

Fill in the blank with the correct word or phrase.

Breaking a number like 13 into 10 and 3 is called — Select —10known factsnear doubles153partitioningcompensationtencounting on.

Fill in the blank with the correct word or phrase.

If you solve 12 – 5 by thinking 12 – 2 – 3, you are subtracting to reach a friendly — Select —531known factsnear doublespartitioningtencompensation10counting on.

Solve the following mentally using the best strategy.

7 + 8 — Select —12153228507292322

Solve the following mentally using the best strategy.

12 – 5 — Select —50287152329321222

Solve the following mentally using the best strategy.

9 + 6 — Select —72832502922151223

Solve the following mentally using the best strategy.

15 + 7 — Select —75015231229282232

Solve the following mentally using the best strategy.

20 – 8 — Select —12292371528503222

Solve the following mentally using the best strategy.

23 + 9 — Select —29152250233228712

Solve the following mentally using the best strategy.

35 – 7 — Select —22122923327152850

Solve the following mentally using the best strategy.

18 + 11 — Select —28152212502923327

Solve the following mentally using the best strategy.

42 – 19 — Select —22750321229232815

Solve the following mentally using the best strategy.

25 + 25 — Select —22715501232232829

Solve the following mentally using the best strategy.

30 – 12 — Select —43453153185965752578

Solve the following mentally using the best strategy.

48 + 5 — Select —31251875595345437865

Solve the following mentally using the best strategy.

63 – 4 — Select —53597518314365782545

Solve the following mentally using the best strategy.

17 + 8 — Select —31251878435965754553

Solve the following mentally using the best strategy.

50 + 28 — Select —45182531786553594375

Solve the following mentally using the best strategy.

75 – 30 — Select —59754345317853186525

Solve the following mentally using the best strategy.

13 + 18 — Select —25594575653143537818

Solve the following mentally using the best strategy.

90 – 25 — Select —43592578455365187531

Solve the following mentally using the best strategy.

36 + 7 — Select —53255943451865753178

Solve the following mentally using the best strategy.

81 – 6 — Select —59187875536543254531

Solve the following mentally using the best strategy.

40 + 26 — Select —676617623347602535

Solve the following mentally using the best strategy.

55 – 8 — Select —476625671762603533

Solve the following mentally using the best strategy.

6 + 19 — Select —604766256733173562

Solve the following mentally using the best strategy.

100 – 40 — Select —254766603367623517

Solve the following mentally using the best strategy.

28 + 5 — Select —606617473562336725

Solve the following mentally using the best strategy.

72 – 5 — Select —676035256662331747

Solve the following mentally using the best strategy.

45 + 17 — Select —661735624760336725

Solve the following mentally using the best strategy.

50 – 15 — Select —476260661725333567

Solve the following mentally using the best strategy.

9 + 8 — Select —254767331735626066