Reading a Ruler with Precision Accuracy Counts Measure Twice Cut Once

#1 reason kids get measuring WRONG…not noticing where the 0 is located! Notice where the "0" line falls on the ruler. Some rulers have this line at the exact edge of the ruler and other rulers place this line slightly to the right of the edge. The location of the "0" line is important for accurate measuring because you must place this point on the ruler at the exact edge of the item or space you're measuring. BOTH RULERS ARE CORRECT TOOLS FOR MEASURING! IT IS YOUR REPSONSIBILITY TO ALWAYS START MEASURING AT THE ZERO!

1 The distance is representing a full inch.

1 1 2 The full inch is divided into two sections. The number of sections determines the denominator. Notice the line height. 1 2 1

1 1 2 Each half inch section is divided into two sections. Notice the line height. It’s getting smaller. Remember the number of sections determines the denominator. What will the denominator be for the new lines? 1 2 1

1 2 1 4 1 4 3 Each half inch section is divided into two sections. Notice the line height. It’s getting smaller. The denominator is 4 because of the 4 sections created by the new lines. 1 2 1 4 1 4 3

Each forth inch section is divided into two sections. Notice the line height. It’s getting smaller. The denominator is 8 because of the 8 sections created by the new lines. 1 2 1 4 1 4 3 8 1 8 3 8 5 8 7

Each eighth inch section is divided into two sections. Notice the line height. It’s getting smaller. The denominator is 16 because of the 16 sections created by the new lines. 1 2 1 4 1 4 3 8 1 8 3 8 5 8 7 16 1 16 3 16 5 16 7 16 9 16 11 16 13 16 15

You now know all the fractions on a common school ruler. But how can you tell the fractions just by look at the line heights? 1 2 1 4 1 4 3 8 1 8 3 8 5 8 7 16 1 16 3 16 5 16 7 16 9 16 11 16 13 16 15

1 PAY CLOSE ATTENTION NOW You can tell what the fraction is for each line by covering the lines up. 1

PAY CLOSE ATTENTION NOW Cover the lines up. 1

1 PAY CLOSE ATTENTION NOW NOW expose the first set of lines. HOW many sections are created? 1

2 sections. That tells me the denominator 1 2

1 1 2 Count by odd numbers for the numerator. Remember the 2 sections. That tells me the denominator. 1 2 1

1 1 2 4 4 Expose the next set of lines. The number of sections created tells me the denominator. 1 2 1 4 4

Count by odd numbers for the numerators. 1 2 1 4 1 4 3

1 1 2 1 3 4 4 8 8 8 8 Expose the next set of lines. The number of sections created tells me the denominator. 1 2 1 4 1 4 3 8 8 8 8

Count by odd numbers for the numerators. 1 2 1 4 1 4 3 8 1 8 3 8 5 8 7

Expose the next set of lines. The number of sections created tells me the denominator. 1 2 1 4 1 4 3 8 1 8 3 8 5 8 7 16 16 16 16 16 16 16 16

Count by odd numbers for the numerators. 1 2 1 4 1 4 3 8 1 8 3 8 5 8 7 16 1 16 3 16 5 16 7 16 9 16 11 16 13 16 15

All the red fractions can be reduced. Do you see any patterns? 1 2 1 4 3 4 1 8 1 8 3 8 5 8 7 16 1 16 2 16 3 16 4 16 5 16 6 16 7 16 8 16 9 16 10 16 11 16 12 16 13 16 14 16 15

METRIC RULER – MILLIMETERS & CENTIMETERS