Multiplication and division become much easier when mathematicians are dealing with the number 10 as a factor or divisor. Use the examples to get scholars noticing number patterns if they haven't already learned this. They divide 20 numbers by 10, multiply 20 more numbers by 10, and finally divide 20 larger numbers by 10. Demonstrate place value using number cards, showing how a zero is added or the last number is taken away with each of these. There are no decimals or fractions here.