Find a missing part when one part and the whole is known | Exit Quiz | Oak National Academy

How many cubes is the whole made up of?

• 2

• 3

• 4

• 5

Answer explanation

5 cubes make up the whole.

Sofia has 3 counters and Jun has 2 counters. Which part-part-whole model correctly shows the parts combining to make the whole?

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• 
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Answer explanation

The second model is correct.

How many cubes are in the missing part?

• 1

• 2

• 3

• 4

• 5

Answer explanation

There is 1 cube in the missing part because 3 can be partitioned into 2 and 1.

Sofia thinks the missing part will be 3. Is this correct?

• Yes

• No

Answer explanation

No. 5 can be partitioned into 3 and 2. We already have 3, so the missing part is 2.

Jun thinks the missing part will be the same for these part-part-whole models. Is he correct?

• Yes

• No

Answer explanation

Yes. Even though the number of red counters changes, the number of yellow counters is the same each time. The missing parts are all 1, representing the 1 yellow counter.

Sofia thinks the missing part will be the same for these part-part-whole models. Is she correct?

• Yes

• No

Answer explanation

No. Both the number of red counters and the number of yellow counters changes each time. The missing parts cannot be the same. The missing parts are 1, 2 and 3.