The working rule of multiplication of a decimal by 10, 100, 1000, etc... are:
1. To multiply a decimal by 10, move the decimal point in the multiplicant by one place to the right.
For examples:
(i) 834.7 × 10
Here we multiplied the number 834.7 by 10 so we move 1 place to the right.
Or,
834.7 × 10
= (8347/10) × 10
= 8347/1
= 8347
(ii) 73.5 × 10 = 735
(iii) 100.9 × 10 = 1009
2. To multiply a decimal by 100, move the decimal point in the multiplicant by two places to the right.
For examples:
(i) 98.26 × 100
Here we multiplied the number 98.26 by 100 so we move 2 places to the right.
Or,
98.26 × 100
= (9826/100) × 100
= 9826/1
= 9826
(ii) 6.006 × 100 = 600.6
(iii) 0.77 × 100 = 77
3. To multiply a decimal by 1000, move the decimal point in the multiplicant by three places to the right.
For examples:
(i) 793.41 × 1000
Here we multiplied the number 793.41by 1000 so we move 3 places to the right.
Or,
793.41 × 1000
= (79341/100) × 1000
= 79341 × 10
= 793410
(ii) 9.15 × 1000 = 9150
(iii) 0.017 × 1000 = 17
4. To multiply a decimal by 10, 100, 1000, etc. move the decimal point of the multiplicant as many places to the right as there are zeroes in the multiplier.
For examples:
(i) 1854.347 × 10
Here we multiplied the number by 10 so we move 1 place to the right.
(ii) 72.4 × 100
Here there is only one place after the decimal and 100 has two zeros, so we put one zero at the end of the number.
(iii) 887.43 × 1000
Only 2 places are there after the decimal, but 1000 has 3 zeros, so we put one zero at the end of the number.
Note: Remember that in multiplication of a decimal by 10, 100, 1000, etc. the decimal will be moved to the right by as many places as the number of zeroes in the multiplier and when the number of zeros is more than the digits after the decimal number, then extra zeros must be added to the product.
● Decimal.
Expanded form of Decimal Fractions.
Changing Unlike to Like Decimal Fractions.
Comparison of Decimal Fractions.
Conversion of a Decimal Fraction into a Fractional Number.
Conversion of Fractions to Decimals Numbers.
Addition of Decimal Fractions.
Problems on Addition of Decimal Fractions
Subtraction of Decimal Fractions.
Problems on Subtraction of Decimal Fractions
Multiplication of a Decimal Numbers.
Multiplication of a Decimal by a Decimal.
Properties of Multiplication of Decimal Numbers.
Problems on Multiplication of Decimal Fractions
Division of a Decimal by a Whole Number.
Division of Decimal Fractions by Multiples.
Division of a Decimal by a Decimal.
Division of a whole number by a Decimal.
Properties of Division of Decimal Numbers
Problems on Division of Decimal Fractions
Conversion of fraction to Decimal Fraction.
5th Grade Numbers Page
5th Grade Math Problems
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