Minus, or subtraction, is a natural extension of counting. To start, you simply count which ones are not crossed off.
Eventually, it will be helpful if the child memorizes the minus table for numbers from 0 to 9.
Minus Worksheets
Arranged from easiest to hardest. These are all positive numbers, and the top number (minuend) is always more or the same as the bottom number (subtrahend). Terms used: Minuend − Subtrahend = Difference
Minus Worksheets: Just Problems, No Pictures
Arranged from easiest to hardest