Question

Aldo must choose a number between55 and101 that is a multiple of 2,6 and 10 . Write all the numbers that he could choose. If there is more than one number, separate them with commas.

Answer 1

60, 90

Explanation:

Since they need to be a multiple of all 3 numbers, it narrows the answers possible.

The numbers that are multiples of 2 in the range are:

56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100

The numbers that are multiples of 6 in the range are:

60, 66, 72, 78, 84, 90, 96

The numbers that are multiples of 10 in the range are:

60, 70, 80, 90, 100

By finding all the multiples, you will find the only 2 numbers that match between all 3 are 60 and 90.

There is a simpler way of doing this as well, but it is not as visual as the first method.

With a multiple of 10, you know the number will always end with a 0, so that limits the options greatly. Also, you know that any number that ends with a 0 is a multiple of 2, meaning that any multiple of 10 is also a multiple of 2.

So all you have to do is find the multiples of 6 in the range that end with a 0, and those are your numbers.

So for this, it would be 60 and 90.

Hope this helps!