October 11, 2011

Use a Ruler As a Number Line


In math, primary students begin with concrete objects, progress through symbols, and arrive at abstract concepts of numbers. A number line is a great tool to help them along this path. Sometimes we forget, but a ruler is a perfect number line. Here's why:

  • A ruler goes from zero to twelve or thirty, depending on whether you are looking at the inch side or the centimeter side.
  • A ruler is in most kids' desks or pencil cases already, so there's no need to print out a paper number line and laminate it. (Having said that, if you do want a printable number line, there are several to choose from.)
  • A ruler is concrete in the sense that it's a real thing that students can touch.
  • Bonus! A ruler leads gently and naturally into fractions and decimals. ("Teacher, what are the little lines for between the numbers?")
So don't just use that ruler for measuring things and drawing straight lines. Use it for counting (including skip-counting), adding, subtracting, and introducing decimals and fractions.

Do you like the ruler in the photo above? Here is a link to that classic, brass-edged 12-inch wooden ruler on amazon.

Question: In your teaching, do you use objects in ways other than their "real purpose?" If so, please share in the comments.

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