Numbers have decimals in between them. For example, between 1 and 2 are the decimals: 1.1, 1.2, 1.3 through 1.9, then it rounds up to 2.
If we need to move up a decimal, we move that same number of times. To go from .5 to our whole number, we move 5 times. .6, .7, .8, .9, then rounding up to 2.
To go from 1.5 to 2 we have to add .5.
Then we just go from 2 to 3. This is 1 whole number.
So the difference is 1.5
3-1.5=1.5
(Or to see it easier 1.5 + 1.5 = 3)
