Decimals

Excel Decimal Number Format

1) What is a Decimal ?
A decimal is a number whose whole number part and the fractional part is separated by a decimal point.
The dot in a decimal number is called a decimal point.
The digits after the decimal point show a value that is less than one
The digits before the decimal point is always a whole number

2) What is the Decimal Place Value Line ?

Everything after the decimal point always has a "th" at the end.
Reading the numbers are the decimal point correctly.
514.89 is eight, nine and not eighty nine.

3) Can all decimals be converted to an equivalent fraction ?
Yes

4) What is 6.996 rounded to 2 decimal places ?
Look at the third digit and round up.
7.00

5) How do we Convert a Decimal to a Fraction ?
Place the decimal number over its place value.
For example, in 0.6, the six is in the tenths place, so we place 6 over 10 to create the equivalent fraction, 6/10

6) Change these Decimals to Fractions ?
0.7 = 7/10
1.5 = 3/2
2.4 = 24/10
0.33 = 33/100
0.03 = 3/100

7) How do we Convert a Decimal to a Percentage ?
Multiply the decimal by 100 and add percentage symbol (%).

8) Change these Decimals to Percentages ?
0.7 = 70%
1.5 = 150%
2.4 = 240%
0.03 = 3%

9) How do we Add Decimals ?
step 1) Write down the numbers, one under the other, with the decimal points lined up.
step 2) Put in any extra zeros so the numbers have the same length.
step 3) Add, using column addition, remembering to put the decimal point in the answer.

10) How do we Subtract Decimals ?
Exactly the same as adding, except this time we subtract instead.

11) How do we Multiply Decimals ?
You do not have to line up the decimal points.
step 1) ignore the decimal point, work out using whole numbers
step 2) count the number of digits after the decimal places
step 3) give the answer the same number of decimal places

12) What is 0.3 * 3 ?
0.9

13) What is 0.3 * 0.3 ?
0.09

14) What is 0.25 * 0.25 ?

There are four digits after the decimal places.
0.25 * 0.25 = 0.0625

15) What is 4.3 * 4.3 ?

There are two digits after the decimal places.
18.49

16) How do you multiply a decimal by 10 ?
To multiply a decimal by 10, move the decimal point 1 place to the right.

17) How do you multiply a decimal by 100 ?
To multiply a decimal by 100, move the decimal point 2 places to the right.

18) How do you multiply a decimal by 1000 ?
To multiply a decimal by 1000, move the decimal point 3 places to the right.

19) What is £3.20 multiplied by 42 ?

There are two digits after the decimal places.

20) How do we Divide Decimals ?

21) What is 13.50 divided by 90 ?
This method is called Short Method.
The Long Method is explained in the Numbers section.

22) What is half of £2.56 ?

23) What is 95 divided by 4 ?

24) What is 7894 divided by 16

25) A truck holds 1589kg of sugar.
It is divided equally into five containers. How much sugar is there in each container ?
317.8 kg

26) What is £573 divided by 4 ?
143.25

27) How do you divide a decimal by 10 ?
To divide a decimal by 10, move the decimal point 1 place to the left.

28) How do you divide a decimal by 100 ?
To divide a decimal by 100, move the decimal point 2 places to the left.

29) How do you divide a decimal by 1000 ?
To divide a decimal by 1000, move the decimal point 3 places to the left.

30) What is 3.244 rounded to 1 decimal place ?
Look at the 2nd digit and round down.
3.2

31) What is a Repeating Decimal
Also known as a Recurring Decimal.
The same pattern of numbers carries on repeating itself forever.
One third is an example of a repeating decimal.

32) Which number has the closest value to 2 ?
1 19/25 , 172.8% , 1.73 , 172.9% , 1 19/26

Converting Decimal to Fraction

the first digit after the decimal point is a tenth
the second digit after the decimal point in a hundred

Converting Decimal to Percentage

multiply by 100

Decimal Places

Rounding