70 Part 1: The World of Numbers
Different Names, Same Number
Decimal fractions can sometimes go by more than one name. If you write 3.82, you read that as
“three and eighty-two hundredths.” You have three wholes and eighty-two of the fractions that
are created by breaking one into 100 parts. Those eighty-two hundreds can make 8 groups of ten
hundredths or eight tenths, with two hundredths left over, so there’s an 8 in the tenths place and
a 2 in the hundredths place.
Now suppose you write 3.820, which you’d read as “three and eight hundred twenty thousandths.”
You read this number differently because it fills in the thousandths place, but its value is exactly
the same as 3.82. All you added was zero thousandths—nothing!
Trailing zeros at the end of a decimal fraction change the way you read the name of the number,
but they don’t change the value of the number. The numbers 1.7, 1.70, and 1.700 all have the same
value. They would be read as “one and seven tenths,” “one and seventy hundredths,” and “one
and seven hundred-thousandths,” but they’re all worth the same amount. If you wrote them as
common fractions, 1.7 would be 1^7
10
, 1.70 would be 1^70
100
, which reduces to 1^7
10
, and 1.7000 would
be 1^700
1000
, which also reduces to 1^7
10. As a result, you’ll often want to drop any trailing zeros to
make the look of the number simpler.
4 tenths 40 hundredths5
CHECK POINT- Write the number 9.003 in words.
- Write the number 82.4109 in words.
- Write the number “forty-two hundredths” in numerals.
- Write the number “forty-two ten-thousandths” in numerals.
- Write the number “three hundred twelve and nine hundred one thousandths”
in numerals.