J's answer to Help's Secondary 1 Maths Singapore question.
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HCF = 6 = 2 × 3
LCM = 756 = 2² × 3³ × 7 (do your prime factorisation)
The HCF tells you that the two numbers have only one '2' and one '3' in common.
The LCM tells you that one of the numbers must have 2² and the other only has 2. One of the numbers must have 3³ while the other only has 3. One of the numbers must have 7, the other doesn't have any 7.
Since both numbers are smaller than 100, the only possible set of numbers is :
2² × 3 × 7 = 4 × 3 × 7 = 84 and 2 × 3³ = 54
LCM = 756 = 2² × 3³ × 7 (do your prime factorisation)
The HCF tells you that the two numbers have only one '2' and one '3' in common.
The LCM tells you that one of the numbers must have 2² and the other only has 2. One of the numbers must have 3³ while the other only has 3. One of the numbers must have 7, the other doesn't have any 7.
Since both numbers are smaller than 100, the only possible set of numbers is :
2² × 3 × 7 = 4 × 3 × 7 = 84 and 2 × 3³ = 54
Date Posted:
3 years ago
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