For this case we have that by definition, the subtraction property of equality establishes that having an equality, any number that is subtracted from one side of it, must be subtracted from the other side.
We have:
So, for it to be fulfilled:
We must subtract "20" on both sides of the equation:
If a tablet weighs 1.23 pounds, the weight written as a mixed number would be, 1 as the whole number and 23 is in the hundreds place, so you would write, 1 and 23/100.