Han Zhi Yuan's answer to ｊｕｎｅ ｔａｎ's Primary 6 Maths Measurement Singapore question.
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The sum of a 3-digit number and 8 is a multiple of 5.
8 = 5(1) + 3
The difference between the same number and 4 is a factor of 143.
Remember that 143 = 11 * 13. Therefore its factors are 1, 11, 13 and 143.
Let's try the smallest 3-digit number 100. The difference between 100 and 4 is 96. If we had chosen a bigger 3-digit number, the difference will increase.
1, 11 and 13 are smaller than 96. The only factor larger than 96 is 143 itself.
Hence the number is 143 + 4 = 147.
You can check that 147 and 8 gives 155, which is a multiple of 5.
8 = 5(1) + 3
The difference between the same number and 4 is a factor of 143.
Remember that 143 = 11 * 13. Therefore its factors are 1, 11, 13 and 143.
Let's try the smallest 3-digit number 100. The difference between 100 and 4 is 96. If we had chosen a bigger 3-digit number, the difference will increase.
1, 11 and 13 are smaller than 96. The only factor larger than 96 is 143 itself.
Hence the number is 143 + 4 = 147.
You can check that 147 and 8 gives 155, which is a multiple of 5.
Date Posted:
4 years ago
P.S. Ignore the 8 = 5(1) + 3 line, have a good weekend ahead! ^^
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