5. Multiplication of decimals |
Name: ______________________________________ Subject: _______________________ Date: _______
Write the missing word
Each side of a square is 1.3 meters. How much is the sum of its four sides? We can add or subtract.t.
1,3
x 4
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5,2
When a whole number is multiplied by 10, we can simply add a zero to the end. Example: 65 x 10 = 650
When a whole number is multiplied by 100, we add two zeros to the end: Example: 7 x 100 = 700
When a whole number is multiplied by 1000, we add three zeros to the end. Example: 523 x 1000 = 523000
Solve these multiplications:
5 x 100 = |
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48 x 10 = |
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7 x 1000 = |
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32 x 10 = |
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128 x 100 = |
To multiply a decimal number by a whole number, first we have to ignore the decimal point and multiply the digits. Then we have to place the decimal point in the result so that it has the same number of decimal places as the number being multiplied
Ejemplo: 5,4 x 10 = 54; 0,7 x 100 = 70; 0,123 x 1000 = 123
0,01 x 100 = |
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15,3 x 1000 = |
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0,00025 x 10 = |
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2,1 x 100 = |
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0,25 x 1000 = |
To multiply a decimal number by a whole number, first we have to ignore the decimal point and multiply the digits. Then we have to place the decimal point in the result so that it has the same number of decimal places as the number being multiplied
Ejemplo: 2,57
x 6
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15,42
Write these operations on a paper and solve these problems.
127 x 9,5 = |
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6,25 x 5 = |
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1,26 x 17 = |
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9,20 x 15 = |
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147 x 12,1 = |
To multiply a decimal by another decimal, we must ignore the decimal points and multiply the digits. Then, we must count the total number of decimal places in both decimal numbers being multiplied; and we must place a decimal point in the result so that it has the same number of decimal places as the total number of decimal places in the two numbers being multiplied.
Ejemplo: 13,5,5
x 0,03
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0,405
Write these operations on a paper and solve these problems.
5,3 x 1,12 = |
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3,4 x 6,12 = |
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1,15 x 12,25 = |
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1,125 x 300,7 = |
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8,32 x 1,01 = |
Ask how formulate problemas and then solve them:
A father gave 2.55 euros to each of his three children. |
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One bottle of wine has 1.50 liters and another bottle has 2.50 liters.
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One bread is 0.75 kilograms. |
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Santiago had $ 8.75 and he spent $ 3.25 on school supplies. |
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A pear is 0.12 kilos. How much will 9 pears weigh? |
®Arturo Ramo García.-Record of intellectual property of Teruel (Spain) No 141, of 29-IX-1999 Plaza Playa de Aro, 3, 1º DO 44002-TERUEL