Numerical Precision
Numerical precision is how many exact digits you use when writing a number in a math problem.
Think of it this way
A measuring cup has markings for 1 cup, 1/2 cup, and 1/4 cup. The more lines on the cup, the more exact your measurement can be. A cup with only one line gives a rough amount. A cup with many lines gives a precise amount.
Explaining numerical precision by grade level
When you do math, the numbers you write down matter a lot. If you round a number, your answer changes a little. Do the same problem many times with rounded numbers, and the answer can change a lot. Even small changes in your numbers can lead to big changes in your result.
