Why are numbers that have 0 in the ones column divisible by 10?

Effectively when you divide by 10, you move the decimal point one place to the left. Imagine if every integer has a decimal component of 0, therefore, 70.0 / 10 = 7.00.

Similarly, but using an incompatible example, 74.0 / 10 = 7.40, which is not an integer.