A decimal represents a fractional amount less than one whole number. Decimals are commonly used to represent monetary amounts, such as 13.45 rupees. The digits after the decimal point indicate fractional portions of the whole number amount. It is important to understand decimals in order to properly comprehend monetary and other measured values that include fractional amounts. Basic math operations like addition, subtraction, multiplication and division can be performed with decimals by properly aligning the decimal points.

1. decimals

2. What is a Decimal?

3. What is a decimal?
A decimal is similar to a fraction in that it is
not a whole number. It is a part of a
number. We use decimals most often
when we are talking about money.
RS13.45
How would you read this number?

4. RS 13.45
THIRTEEN RUPEES POINT FOURTY
FIVE PAISE .
REMEMBER WE DO NOT USE
PAISE WHEN AMOUNT IS less
THAN RS 1

5. What does the .45 mean?
.45 IS SAME AS SAYING 45 PAISE IT
MEANS ONLY A PART OF RUPEES . IT
IS NOT WHOLE MONEY. WE STILL
NEED TO GET THE WHOLE THING

6. Why do I have to understand
decimals?
This is a good question. We need to understand
what the value of each number means in order to
understand what we are talking about. Here is
an example
Here is an example:
A shirt costs RS 12.05, but when I wrote the
number down I wrote RS 12.5. What is wrong
with this?

7. Why is RS12.5 wrong?
RS 12.5 really is saying RS 12.50,
because when we read how much
something costs it always has two places
after the decimal point. If we don’t have a
number after the first number we must
assume it is a zero. However, when we
read $12.05, the zero is the place holder
so we know it is 5p and not 50p. That is a
45¢ difference. I can get a piece of gum
for that amount!

8. How do I read a decimal?
If you look at the number 12.3, you say 12
and 3 tenths.
If you look at the number and it says 12.35,
you say 12 and 35 hundredths.
If you look at a number and it says 12.05,
you say 12 and 5 hundredths.

9. Let’s Write this in Expanded
Notation
If we are using money, it would look like
this:
RS100 + RS 30 + RS 7 + 80P + 2 P = RS
137.82.
If we are not using money, it would look
like this:
100 + 30 + 7 + .8 + .02 = 137.82

10. How do I know how large a decimal
is?
If you see two numbers that are decimals, one
says 7.3 and the other says 7.003, you look at
how many places the number that is longer
has. You make both numbers the same
length by adding zeros to the end of the
shorter number. So the numbers read:
7.300 or 7.003
Now when you look at the number you can see
which is larger: 7.300

11. Which is larger?
1) 4.5 or 4.05
Because 4.5 equals 4.50, 50 is larger than 5
2) 6.003 or 6.3
Because 6.3 equals 6.300, 300 is larger than
3
3) 5.012 or 5.12
Because 5.12 equals 5.120, 120 is larger
than 12

12. When else do we use decimals?
• Weight (He weighed 85.5 lbs)
• Temperature (It was so cold today, it
was only 43.7 )
• Measuring distances (example, the race
was a 5 K, but since I don’t understand
kilometers, I changed it to miles and
saw that the race was 3.1 Miles long)
• Can you think of any other times?

13. Addition of decimals
• To add decimals, follow these steps:
• Write down the numbers, one under the
other, with the decimal points lined up
• Put in zeros so the numbers have the
same length
• Then add normally, remembering to put
the decimal point in the answer

14. Example: Add 3.25, 0.075 and 5
• Line the decimals up: 3.25
0.075
+5
= : 3.250
0.075
+5.000
Ans 8 .325

15. Subtracting Decimals
• To subtract decimals, follow these steps:
• Write down the two numbers, one under
the other, with the decimal points lined up.
• Add zeros so the numbers have the same
length
• Then subtract normally, remembering to
put the decimal point in the answer

16. Example: Calculate 7.005-0.55
Line the decimals up: 7.005
-0.55
= : 7.005
-0.550
ans = 6. 455

17. How to Multiply Decimals
Multiply normally, ignoring the decimal
points.
Then put the decimal point in the answer -
it will have as many decimal places as the
two original numbers combined.
In other words, just count up how many
numbers are after the decimal point
in both numbers you are multiplying, then
the answer should have that many
numbers after its decimal point.

18. Dividing Decimals
To divide a decimal number by a whole
number:
Use Long Division (ignoring the decimal
point)
Then put the decimal point in the same spot
as the dividend (the number being divided)

19. Dividing by a Decimal Number
The trick is to convert the number you are
dividing by to a whole number first,
by shifting the decimal point of both
numbers to the right:
It is safe to do this if you remember to shift
the decimal point of both numbers the
same number of places.