3. Red blocks weigh 10 grams Green blocks weigh 13 grams Mary has x red blocks. In terms of x how much do Mary’s red blocks weigh? Click on the scales to find out

4. Each red block weighs 10 grams Mary has x red blocks. x 10 Multiply the number of blocks by the weight x x 10 We write this as 10 x

5. Red blocks weigh 10 grams Green blocks weigh 13 grams Mary has x red blocks. She has 3 more green blocks than red blocks. In terms of x how many green blocks does Mary have? Click on the scales to find out This has nothing to do with weight. !

6. She has three more green blocks. Mary has x red blocks x 3 So there are the same number of green blocks as red ( x ) plus another 3 x + 3

7. Red blocks weigh 10 grams Green blocks weigh 13 grams Mary has x red blocks. Mary has x + 3 green blocks How much do the green blocks weigh? Click on the scales to find out

8. Multiply the weight by the number of blocks x + 3 Green blocks weigh 13 grams Mary has x + 3 green blocks 13 x We write this as 13 x + 39

9. Click on the scales to find out

10. There are x red blocks and they weigh 10g each 10 x There are x + 3 green blocks and they weigh 13g each 13 x + 39 Total weight of blocks 23 x + 39