To quickly multiply a whole number by we simply place a zero at the end of the number.
For example, to find we join together and
Andrey bought $10$ boxes of candies. If each box contains $30$ candies, how many candies did Andrey buy? Express your answer as a whole number.
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a
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b
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c
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d
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e
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Multiplying a whole number by is similar to multiplying by However, this time, we attach two zeros to the end of the number.
For instance, to find , we join together and
Find the value of
To find we join together and
$9 \times 100 =$
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a
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$90$ |
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b
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$9,100$ |
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c
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$900$ |
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d
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$109$ |
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e
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$9,000$ |
$42 \times 100 =$
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a
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$420,000$ |
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b
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$42,000$ |
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c
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$420$ |
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d
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$42$ |
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e
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$4,200$ |
A power of ten is any whole number where the leading digit is and the remaining digits are all zeros.
For example, the following numbers are all powers of ten:
We can multiply a number by a power of ten by adjoining the number of zeros in the power of ten to the number.
For example, to calculate we first count the number of zeros in the power of ten.
Now, to find , we join with the block of zeros:
Therefore,
Find the value of
First, notice that has a block of zeros:
Now, to find we join with the block of zeros:
Therefore,
$6 \times 1,000 =$
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a
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$6,100$ |
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b
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$600$ |
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c
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$6,000$ |
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d
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$6,001$ |
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e
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$60,000$ |
$21 \times 1,000 =$
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a
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$12,000$ |
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b
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$21,000$ |
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c
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$210,000$ |
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d
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$31,000$ |
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e
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$2,100$ |
Find the value of
First, notice that has a block of zeros:
Now, to find , we join with the block of zeros:
Therefore,
$51 \times 10,000 =$
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a
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$510,000$ |
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b
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$51,000$ |
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c
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$5,100$ |
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d
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$51,100$ |
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e
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$15,000$ |
$20 \times 100,000 =$
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a
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$20,000,000$ |
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b
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$2,100,000$ |
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c
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$210,000$ |
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d
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$2,000,000$ |
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e
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$200,000$ |