To simplify, you combine things that are the same kind — like adding up how many x's you have, or how many plain numbers. So this lesson runs on counting and combining equal groups and on quick addition. Warm those up first.
Answer these 3, then press Show my path. No grade — this just points you to the right level.
1. You have 2 apples and 3 more apples. How many apples?
2. 2 boxes plus 4 boxes is how many boxes?
3. Can you add 3 apples and 2 oranges into one number of the same fruit?
You can only combine things of the same kind. Apples go with apples; the x terms go with x terms; plain numbers go with plain numbers. Just count how many of each.
Your quick check picks one for you, but you can switch any time:
Level 0 Count the same kind, one step at a time.
A. 2 cubes + 3 cubes = ___ cubes
2 + 3 = 5 cubes.
B. 4 cubes + 1 cube = ___ cubes
4 + 1 = 5 cubes.
C. 3 dots + 3 dots = ___ dots
3 + 3 = 6 dots.
Level 1 Now the cubes are called x. Add the counts.
A. 3 x's + 2 x's = ___ x's (just the number)
Add the counts: 3 + 2 = 5, so 5x.
B. Write that answer: 3x + 2x = ?
3 + 2 = 5 of the x's, so 5x.
C. 4 + 2 (just the plain numbers) = ___
4 + 2 = 6.
Level 2 Warm up straight into simplifying.
A. Simplify 4x + 3x.
Add the counts: 4 + 3 = 7, so 7x.
B. Simplify 2x + 5 + 3 (combine the plain numbers).
5 + 3 = 8, keep the 2x → 2x + 8.
1. Simplify 2x + 4x.
Add the counts: 2 + 4 = 6, so 6x.
2. Combine the plain numbers: 3 + 5 = ___
3 + 5 = 8.
You've practiced exactly what Lesson 6-7 uses. Time to dive in.
Start Lesson 6-7 →