# 5.12: Write Equations

**Write Equations - Write and Solve Equations with Blocks as Unknowns**

Students are presented with two scales, their contents, and their weights, and explore ways to represent relationships shown in the scales by writing block equations. They gain experience matching equations to scale pictures, and then solving sets or systems of equations without the pictures. It is in this section that students are introduced to the idea that sets of the same type of block can be represented as either the sum of that number of blocks (e.g., ) or as a product (e.g., ).

**Solutions**

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2.

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8.

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13. c

14. b

15. c

16. a

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20.

Try these. Write equations. Figure out the weights of the blocks.

Fill in the numbers.

Circle the equation that matches the scale.

Eric wrote these equations from pictures of scales.

Use Eric’s equations. Find the weight of each block.