Wednesday
Li - To compare decimals
Place value and ordering decimals
Decimal points are used in numbers to separate the whole number from parts of the whole. Like whole numbers, numbers written as decimals can be either positive or negative, for example, 2.6 or -2.6.
Place value
Place value gives the value of each digit in a number. For example, in the number 42, the 4 is worth 4 tens, or 40, and the 2 is worth 2 units, or 2. The same process is true for decimals.
In the number 2.78, the 2 is worth two units, the 7 is worth 7 tenths and the 8 is worth 8 hundredths.
Example
Which is greater, 2.5 or 2.15?
Firstly, both numbers have a 2 in the units , so look at the next digit along. This is the digit in the first decimal place. The first number has a 5 in the tenths column whereas the second number has a 1 in the tenths column. 5 is greater than 1, so that means that 2.5 is greater than 2.15.
