Pete set up an unbalanced 2- pan scale.the right pan went up with 12 cubes.the left pan went down with a bag of cubes and 5 cubes outside the bag.Tom took one cube at a time from the bag with cubes and put each into the left pan.the two pans balanced when Tom had placed 15 cubes into the right pan.How many cubes were in the bag at first?

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Answers

2014-09-04T18:50:01+08:00
15-12=3
3+(15-5)=13
there were 13 cubes from the bag at first

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