The two-digit number ab stands for 10a + b since the first digit represents tens and the second represents units. If 10a + b = 7 (a + b), then 10a + b = 7a + 7b, and so 3a = 6b, or more simply, a ...

Learn activities for fourth grade math to prepare for school. Teach your children 4th grade math skills like fractions, multiplication and division.

For each of the quantitative conceptual structures for 2-digit numbers, a somewhat different triad of relations is established between the number words, written 2-digit marks, and quantities. The ...