Fractions & Decimals

Problem

Find fractions between two on the number line

On a number line from 0 to 1 divided into 12 equal parts, mark the fractions 56\frac{5}{6}, 1112\frac{11}{12}, 12\frac{1}{2}, and 46\frac{4}{6}, then list every one of them that lies between 512\frac{5}{12} and 34\frac{3}{4}.
0 1 1/12 2/12 3/12 4/12 5/12 6/12 7/12 8/12 9/12 10/12 11/12
Fractions
Your answer
How to solve
Strategy Make a Systematic List — Rewriting every fraction over the common denominator 12 (matching the number-line ticks) lets us list each one's position and read off which lie between the two endpoints. The number line is the diagram that anchors the comparison.
1STEP 1

Express the endpoints in twelfths

Write the boundaries over 12: 512\frac{5}{12} stays 512\frac{5}{12}, and 34\frac{3}{4} = 912\frac{9}{12} — so look for fractions between 512\frac{5}{12} and 912\frac{9}{12}.

34=912\frac{3}{4} = \frac{9}{12}
2STEP 2

Convert the four fractions to twelfths

Rewrite each fraction with denominator 12: 56\frac{5}{6} = 1012\frac{10}{12}, 1112\frac{11}{12} stays 1112\frac{11}{12}, 12\frac{1}{2} = 612\frac{6}{12}, and 46\frac{4}{6} = 812\frac{8}{12}.

56=1012,12=612,46=812\frac{5}{6}=\frac{10}{12}, \frac{1}{2}=\frac{6}{12}, \frac{4}{6}=\frac{8}{12}
3STEP 3

List which fall between 512\frac{5}{12} and 912\frac{9}{12}

In twelfths, 612\frac{6}{12} and 812\frac{8}{12} fall inside (512\frac{5}{12}, 912\frac{9}{12}), but 1012\frac{10}{12} and 1112\frac{11}{12} do not — so 12\frac{1}{2} and 46\frac{4}{6} lie between.

512<612,812<9121012,1112\frac{5}{12} \lt \frac{6}{12}, \frac{8}{12} \lt \frac{9}{12} ≤ \frac{10}{12},\frac{11}{12}
Answer
12\frac{1}{2} and 46\frac{4}{6}
In twelfths the target window is 612\frac{6}{12} through 812\frac{8}{12}; 12\frac{1}{2} = 612\frac{6}{12} and 46\frac{4}{6} = 812\frac{8}{12} sit inside it, while 56\frac{5}{6} = 1012\frac{10}{12} and 1112\frac{11}{12} sit past 912\frac{9}{12}, so they are correctly excluded. The marks on the number line agree.
Takeaway

Put every fraction over the same 12 ticks, and you can see at a glance which ones sit in between!

  • Express the endpoints in twelfths
  • Convert the four fractions to twelfths
  • List which fall between 512\frac{5}{12} and 912\frac{9}{12}
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