The sum of three different 3-digit numbers is 507. Of the three numbers, find the largest possible number.
Need a hint?
To get the biggest possible number, the other two numbers must be the smallest they can be. What are the two smallest different 3-digit numbers?
Worked answer
- To make one number as large as possible, the other two numbers must be as small as possible.
- The smallest 3-digit number is 100.
- The next smallest different 3-digit number is 101.
- Sum of the two smallest numbers = 100 + 101 = 201.
- Largest possible number = 507 − 201 = 306.
The mistake this question tests
Calculation slip
Some pupils use 100 and 100 for the two small numbers and get 307, but the three numbers must be different, so the two small numbers must be 100 and 101.
How to fix it at home →Wrong answers children often give:
- 307 Calculation slip
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See the answer →Practise PSLE whole numbers until the mistakes stop.
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