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Fractions and decimals on the number line

Fractions and decimals on the number line

A fraction

Every fraction has a place on the number line. To find 35\displaystyle \frac{3}{5}: cut the segment from 0 to 1 into 5 equal parts, and count 3 parts from 0.

A decimal
0.35 is 35 hundredths: 3 tenths and 5 more hundredths.

For decimals, cut the segment from 0 to 1 into 10 parts – tenths. 0.35\displaystyle 0.35 is between 0.3\displaystyle 0.3 and 0.4\displaystyle 0.4. Zoom in there and cut into 10 again – hundredths: 0.35\displaystyle 0.35 is exactly halfway.

A mixed number

315\displaystyle 3\frac{1}{5} is between 3 and 4: from 3, one fifth of the way to 4.

Numbers between numbers

Zoom in between 0.5\displaystyle 0.5 and 0.6\displaystyle 0.6: cut it into 10 parts, and there are 0.51\displaystyle 0.51, 0.52\displaystyle 0.52 … 0.59\displaystyle 0.59. Zoom in again between two of them, and there are more. Between any two numbers there is always another number – as many as you like.

Exercise 1

Draw a segment from 0 to 1 and place on it, roughly, 56\displaystyle \frac{5}{6} and 0.35\displaystyle 0.35.

Exercise 2

Place, roughly, 0.72\displaystyle 0.72, 0.27\displaystyle 0.27, 0.027\displaystyle 0.027 and 0.270\displaystyle 0.270 on a number line.
Two of them fall on the same point – which, and why?

Exercise 3

Find three numbers between 0.11\displaystyle 0.11 and 0.12\displaystyle 0.12.
How many such numbers are there, do you think?