Page 11 - 新思维数学学生用书5 样章

1 The number system

1.1 Understanding place value

We are going to …

• explain the value of a digit in a decimal number (tenths and hundredths)

• multiply and divide whole numbers by 1000

• multiply and divide decimals by 10 and 100.

It is very important for a doctor

to give the correct amount of – 15 ml
medicine. A dose of 10 ml is ten – 10 ml

times greater than a dose of 1 ml – 5 ml
and ten times smaller than

a dose of 100 ml.

compose decimal number decimal place
decimal point decompose hundredth

place value tenth

The value of a digit depends on its position in the number.
Think about what the digit 5 is worth in these numbers.

ater
Water
Water
Water
W
ate
W
Water
Water Water r W ater 2.35 m
$1.50
0
$1.50
$1.50
$1.50 $1.50 $1.50 25
$1.50
$1.50
$1.5
cents
10