Money is fractions in disguise
$0.50 is just half a dollar, $0.25 a quarter — decimals are fractions written another way, in tenths and hundredths. Once you see money as decimals, the decimal point stops being mysterious.
Decimals are fractions in disguise
A decimal is another way to write a fraction whose denominator is 10 (or 100, or 1000). The decimal point separates whole things from parts of a thing. 0.7 means 7/10 — seven pieces out of ten.
3/10 = 0.3 · 1/2 = 5/10 = 0.5 · $0.25 is 25 cents, which is 25/100 of a dollar
Money is decimal practice
Every price tag is a decimal! A dollar is the whole and cents are hundredths. $1.50 means one whole dollar and 50/100 more.
Lab · The coin decimal machine
- Gather (or imagine) 10 dimes. Ten dimes make one dollar, so one dime is 1/10 of a dollar, which is $0.10.
- Count out 3 dimes and write the amount as a decimal.
- Count out 7 dimes and write that as a decimal too.
- Check: 3 dimes plus 7 dimes should add up to exactly $1.00. Do your decimals add up?
What you should see: You used real money to see that tenths written as decimals add up just like whole numbers do.