Decimals PowerPoint

1. DECIMALS
Made by Kartik Gupta 7D

2. What are decimals ?
• Decimals are parts of whole numbers. They
are a little like fractions but we write them in a
different way. Decimal numbers have a
decimal point. This separates the whole
numbers (on the right) from the part numbers
(on the left)

3. Place value of decimals

4. Comparison of decimals
• If there are two decimal numbers we can compare
them. One number is either greater than, less than
or equal to the other number.
• Therefore, when decimals are compared start with
tenths place and then hundredths place, etc. If one
decimal has a higher number in the tenths place then
it is larger than a decimal with fewer tenths. If the
tenths are equal compare the hundredths, then the
thousandths etc. until one decimal is larger or there
are no more places to compare. If each decimal place
value is the same then the decimals are equal.

6. Multiplication of decimals
To multiply decimal numbers:
• Multiply the numbers just as if they were whole
numbers.
• Line up the numbers on the right - do not align the
decimal points.
• Starting on the right, multiply each digit in the top
number by each digit in the bottom number, just as
with whole numbers.
• Add the products.
• Place the decimal point in the answer by starting at
the right and moving a number of places equal to the
sum of the decimal places in both numbers multiplied.

8. Division of decimals
• If the divisor is not a whole number, move decimal
point to right to make it a whole number and move
decimal point in dividend the same number of place.
• Divide as usual. Keep dividing until the answer
terminates or repeats.
• Put decimal point directly above decimal point in the
dividend.
• Check your answer. Multiply quotient by divisor. Does
it equal the dividend?

10. Multiplication of decimals by 10, 100, 1000
• The working rule of multiplication of a decimal by 10,
100, 1000, etc... are:
• To multiply a decimal by 10, move the decimal point in
the multiplicant by one place to the right.
• To multiply a decimal by 100, move the decimal point
in the multiplicant by two places to the right.
• To multiply a decimal by 1000, move the decimal point
in the multiplicant by three places to the right.

12. Division by 10, 100, 1000
Division by 10 and 100 and 1000 are explained here step by
step. We know the following facts regarding division process:
• When a number is divided by 10, the digits, except the digit
at the one's place, make the quotient and the digit at one's
place becomes the remainder.
• When a number is divided by 100, the quotient is the number
made by the digits, except the digits at one's and ten's
places. The number formed by ten's and one's digit of the
dividend number is the remainder.
• Following this method, when we divide by 1000, the
remainder will have 3 digits.
When a number is divided by 1000, the quotient is the
number made of the digits except the digits at one's, ten's
and hundred's place. The number formed by these three
digits is the remainder.

14. Division of decimal by decimal
To divide a decimal by another decimal:
• Move the decimal point in the divisor to the right
until it is a whole number.
• Move the decimal point in the dividend to the
right by the same number of places as the
decimal point was moved to make the divisor a
whole number.
• Then divide the new dividend by the new divisor

16. Division of decimal by whole number
The rules to divide a decimal by a whole number are:
• Divide as in division of numbers ignoring the decimal
point.
• When you reach the tenths digit, place the decimal in
the quotient.