Double-digit addition is just one of the many mathematical concepts that students are expected to master in first andsecond grade, and it comes in many shapes and sizes. Many adults are probably comfortable performing double digit addition withregrouping, also called borrowing or carrying. The wor...
single-digit multiplication done twice. It starts off just the same with multiplying the numbers in the ones place, and then you add a second round of multiplication using the numbers from the tens place. After getting the basic formula down, there are also a few tricks you can master in ...