Math: Number lines

One of the most important math tools is the number line. Lining up counters along a number line will provides a concept of number, both value and naming. It can be used to order numbers. An open number line may have the notches on it, but not the numerals. If you laminate it, a dry erase marker can be used or number tokens can be placed along the line. Then the number line can be used for any sequence of numbers, 10s, 100s, etc. If your child learns where the 5 goes, then can she place the 3? the 6?  If this number line is from 20 to 30, where is 25? If this number line is from 100 to 200, where is 150, 175?

Use the number line for rounding. Generally (but not always!), we teach children that 5, 6, 7, 8, 9 numbers are rounded up to the 10, with 4, 3, 2, 1, rounded down. The number line is essential in teaching this concept. Is 4 closer to 0 or to 10? Is 37 closer to 30 or to 40.

Don't forget to use a number line vertically, as well as horizontally. We read number lines for graphing, and for grids. A protractor is a curved number line, and children have to read these with zero on the left or the right, for angles whose vertex is on either side.

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