Number lines are useful for measurement.
The word "rational" comes from the word "ratio" meaning any numbers be written in "x/y" form. Rational numbers include whole numbers or integers, positives, negatives, fractions and decimals. Even repeating decimals are rational numbers. Irrational numbers are numbers that cannot be placed in a ratio. They cannot be counted because their decimal equivalents are infinite. An example of an irrational number is Pi, a number which continues to infinity. Rational numbers or "counting numbers" lend themselves well to placement on a number line. Putting rational numbers on a number line helps students conceptualize size and sequence.
Instructions
1. Draw a horizontal line. Put the value of zero in the middle of the number line. To the left of zero, put
the negative integers up to -10. To the right of zero, put the positive integers up to 10. These are known as major tic marks.
2. Put three minor tick marks between the zero and the one. Since the numbers have been divided by
four, the bottom of the fraction should be four for each of the tic marks,1/4, 2/4, and 3/4. Reduce the 2/
4 to 1/2. The same process repeats for the other numbers, however the whole number to the left also writes as in 1 1/4, 1 1/2 and 1 3/4.
3. Convert the fractions to decimals and write the decimal equivalents above. Divide the numerator by the
denominator to change fractions to decimals -- 1/4 is .25, 1/2 is .50, 3/4 is .75. Repeat the process for the rest of the numbers.
4. Use the number line as a reference to convert between fractions and decimals or as a visual learning tool.
Tags: fractions decimals, number line, decimal equivalents, numbers number, numbers number line