Decimals Tenths and Hundredths

A decimal is another way to write a fraction with denominators of 10, 100, or 1000. The decimal point (.) separates whole numbers from parts. 0.3 means 3 tenths, which is the fraction 3/10. 0.07 means 7 hundredths, which is 7/100. Decimals are used in money, measurements, and everyday life.

The place to the right of the decimal point is the tenths place. The next place right is hundredths. 0.45 means 4 tenths + 5 hundredths, or 45 hundredths. Whole numbers go to the LEFT of the decimal. Parts go to the RIGHT. $2.50 means 2 whole dollars and 50 cents (50 hundredths of a dollar).

0.5 = 5/10 = one-half. 0.25 = 25/100 = one-quarter. 0.75 = 75/100 = three-quarters. 1.5 = one and a half. 3.14 = pi, the special number for circles. Money is all in decimals: $0.50 is half a dollar, $0.01 is a penny, $1.99 is one dollar and 99 cents.

Decimals and fractions are two different ways of saying the same thing. 1/2 = 0.5. 1/4 = 0.25. 3/4 = 0.75. Once you know these common conversions, you can switch between them easily. Decimals are often faster to compare: is 0.3 or 0.4 bigger? Easy — 0.4. Is 3/10 or 2/5 bigger? Harder — you have to convert first.