The worksheets are in PDF format. Multiplication - 2 Digit By 2 Digit - worksheet 21 - 30 (Ten Worksheets).Nov 12, 2018 · Two digit multiplication is one of them. Though some children will pick it up quick others will need multiple exposures and numerous time to practice it. So today, I have a two-digit multiplication worksheet that gets children practicing rounding and solving two-digit multiplication problems….but it is more fun than just a regular worksheet.
Digit sums and digital roots can be used for quick divisibility tests: a natural number is divisible by 3 or 9 if and only if its digit sum (or digital root) is divisible by 3 or 9, respectively. For divisibility by 9, this test is called the rule of nines and is the basis of the casting out nines technique for checking calculations.