The common-core math standards require that students learn the standard algorithm for multi-digit adding and subtracting—you know, the process in which you line the numbers up vertically to add or ...

Students put all of their addition and subtraction skills together to solve equations. In this lesson, students put all of their addition and subtraction skills together to solve equations. Julia ...

Students practice addition and subtraction problems without regrouping. In this lesson, students practice addition and subtraction problems without regrouping using base-10 block manipulatives and ...

NARRATION: Back in the deepest, darkest depths of time, there lived a great mathemagician called Hypatia. Numbers fell under her spell one by one. With them, Hypatia could do anything. Now, Hypatia is ...

Mental maths is when you do calculations in your head instead of writing them down. Sometimes, it's just as quick to do calculations in your head as it is to write down every step. You can add and ...