Pencils are sold in boxes of 10, erasers are sold in boxes of 14, a teacher wants to buy the same number of pencils and erasers. Work out the smallest number of boxes of each item she should buy. what' s the answer? i don't get it

10 = 2 x 5

14 = 2 x 7

In order to * cover * those two numbers, you need a 2, a 5 and a 7.

2 x 5 x 7

= 70

That's the lowest common multiple.

Now just divide to get the number of boxes.

70 / 10 = 7 boxes of pencils

70 / 14 = 5 boxes of erasers

She will have to buy 7 boxes of pencils and 5 boxes of erasers. 10*7=70 and 14*5=70