Addition, Subtraction, Multiplication, Division by a whole number, and Division by a decimal.
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Transcript of Addition, Subtraction, Multiplication, Division by a whole number, and Division by a decimal.
OPERATIONS WITH DECIMALS
Addition, Subtraction, Multiplication, Division by a whole number, and Division by a decimal
Additiion
Line up the all decimal points. Add.
2 5 . 3 9 . 7 2 0 . 6 1 8 3 5 ∙ 6 3 8
Subtraction
Line up the all decimal points. Add zeros as place holders Subtract
1 2 . 5 1 2 . 5 0- 9 . 2 6 rewritten - 9 . 2 6
3 . 2 4
Multiplication
Line up digits to be multiplied with decimals.
Multiply. Count the total number of decimal places
in the factors to find out how many decimal places the product has.
Multiplication continued
2 decimal places 1 . 2 91 decimal place x 6 . 2
2 5 87 7 4 .
3 decimal places 7 . 9 9 8
Estimate to check: 1.29 rounds down to 1. 6.2 rounds down to 6. 1 X 6 = 6This product makes sense – the product is close.
Division by a Whole Number
Divide. Put the decimal point in the quotient
directly above the decimal point in the dividend.
3 8 . 7 6
Whole Number Division continued
- 6 .
2 7 - 2 7 .
0 6 - 6
0
3 8 . 7 6
2 . 9 2
Whole Number Division continued
Estimate to check.8 . 7 6 is close to 9
9 ÷ 3 = 3
3 is close to 2 . 9 2
The quotient makes sense.
Division Using Decimals
Step 1 - move the decimal point in the divisor to the right to make a whole number.
0 . 3 4 . 8 6
Division Using Decimals continued
Step 2 – move the decimal point in the dividend the same number of places as in the divisor.
3 4 . 8 6
Step 3 Divide Put the decimal point in the quotient above
the decimal point in the dividend.
1 6 . 2 3 4 8 . 6