### Home > MC1 > Chapter 4 > Lesson 4.2.1 > Problem 4-55

Explore part (a) with the eTool below.

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How can you add or subtract any number of 4's, 5's, and 7's to make 19?

4 + 4 + 4 + 7, or 3(4) + 7, is one way of solving this problem. Can you find at least one more solution?

If you multiply 6 by 3, how far from 25 is the product? Answer that question and use it as a starting point for your solution. Remember to check your work!

Explore part (b) with the eTool below.

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This problem is very similar to parts (a) and (b). Try starting with one number and see how close you can get to 23 using just that number. Then see if one of the other lengths can help you finish.

Explore part (c) with the eTool below.

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