For the first question, you draw a model of two of the same lengths at $37.50 One has more money than another, $10.20.

So the total money donated is the whole amount in the model, 37.5 × 2, and substract the remaining 10.2.



For the second question, the model on the right side shows the total amount of beads, and one block is number of girls.

The top one has 6 beads per girl, so there are 6 blocks in total. The bottom has 6 beads per girl, and the remaining is 8 beads.

Both has the same number of beads, hence same number of blocks. Since the remaining 8 is one whole block, and one block represents the number of girls, there are 8 girls in total. You can check by working backwards with the answer. The bottom part is the algebra way of working it out.

Go try it out! Hope it helps

for question 7