Doodles Do Algebra – Lesson 140

lesson-140Today your child learns how to add and subtract second degree radicals. I think that the basic explanation on the worksheet is enough to help your child through the process. But the basic idea is that there are two steps: first to reduce the radicals that you are adding or subtracting to their simplest form, and then second to add like terms. “Like terms” when you are adding or subtracting radicals is just like the “add like terms” you taught your child back when he first began learning algebra and perhaps you would say to him, “one ‘x’ plus two ‘xes’ equal three ‘xes’.” Sound familiar? If you have worked your child through this curriculum, you will remember saying ‘xes’ many, many times while explaining algebra to him.

Well, adding and subtracting radicals is the same idea, once they have been reduced to their simplest form, only you say “one ‘square root of 2’ plus two ‘square root of 2es’ equals three ‘square root of 2es’,” instead of ‘xes’.

The last question today pushes your child to think about extending the adding and subtracting of second degreee radicals into the realm of constants and unknowns. It is the same principle, and maybe even easier that doing it with numerical values.

If my explanation does not make sense, just let me know in the comments below and I will help you. It is one of those Monday mornings where you cannot seem to drink enough coffee…

Download Lesson 140 of Doodles Do Algebra HERE


1. 5 square root of 3

2. 8 square root of 2

3. 2 square root of 5

4 (a-2c) square root of b