27
36
No. A multiple cannot be less than the number it is compared to. An LCM can never be less than the greatest number in the set.
A two-digit number that is a multiple of 3 and 7 and 1 less than a multiple of 5 is 84, because 84/7=12 and 84/3=28 and 84 is 1 less than 85, and 85 is a multiple of 5 so the answer is 84
123 and 129 meet those specifications.
Not if you include negative numbers.
14
Every prime number except 2 must be odd. This is because if it were even it would be divisible by 2 and so wouldn't be a prime number. The next point to note is that all odd numbers are one more or one less than a multiple of 4. Because 2 more than a multiple of 4 is even, and 3 more than a multiple of 4 is the same as 1 less than the multiple of 4 above. Thus every prime number except 2 must be 1 more or 1 less than a multiple of 4.
65
In that range, every prime number is either one more or one less than a multiple of 4. This also works for 6.
15 is an odd number less than 20.
70, it is a multiple of 2 and 7 is more than 50 but less than 100 and 2*5*7=70 and all those numbers are prime.
84
It is 30.
There are three possible answers. More information is required.
41-- Less than 100-- 42 is the multiple of 7-- 4 + 1 = 5
Any factor of the number less than the number itself.
10 is such a number.