AAA Math
Aaa Math: Adding Two Digit Numbers
This lesson has an explanation for adding two-digit numbers using paper and pencil. There is also a game to practice your skills. The game gives you a percent score of your correct answers, as well as running totals of your correct and...
National Council of Teachers of Mathematics
Nctm: Illuminations: Volt Meter
As you put the different type of batteries on the volt meter pay attention to the voltage equations in the table. See how positive and negative numbers interact.
Illustrative Mathematics
Illustrative Mathematics: k.oa Pick Two
This activity is a basic introduction to writing simple equations. Students are given a set of numbers and will pick two numbers that add to make six. They will write an equation that shows that those two numbers add to make 6.