Generate Equivalent Expressions

How the lesson starts: Generate Equivalent Expressions

Party bag puzzle
Hooray, it's Mo's birthday! Mo packs 4 party bags. Each bag gets x candies and 3 balloons. How many things in all? You could write 4(x + 3), or 4x + 12. Two looks, same amount! Let's learn to rewrite expressions.
Like terms team up
First, Mo has 4 gift boxes, each holding y stickers. That's y + y + y + y. Adding the same thing again and again is multiplying! So y + y + y + y = 4y. Terms with the same letter are like terms, and they can team up. Mo also has 3y stickers and finds 2y more. Like terms add their numbers: 3y + 2y = 5y.
Share the multiply
Now the party bags: 4(x + 3). Picture a rectangle, 4 tall. The top is split into x and 3. The first part is 4 × x = 4x. The second part is 4 × 3 = 12. So 4(x + 3) = 4x + 12. That's the distributive property.