Place Value of Deciamls
Decimal places (tenths, hundreths, thousanths) correspond to fractions (1/10, 1/100, 1/1000).
For Instance:
.2 = 2/10 or two tenths
.34 = 34/100 or thirty four hundredths
.546 = 546/1000 or five hundred forty six thousandths
When you move from one place value to the next, you multiply or divide by ten.
If I multiply .34 x 10, I move the decimal place one place value to the right --> 3.4
If I divide .34 ÷ 10, I move the decimal place one place value to the left --> ._34
- If there is an empty place value in a decimal, I put a zero as a place holder --> .034
For Instance:
.2 = 2/10 or two tenths
.34 = 34/100 or thirty four hundredths
.546 = 546/1000 or five hundred forty six thousandths
When you move from one place value to the next, you multiply or divide by ten.
If I multiply .34 x 10, I move the decimal place one place value to the right --> 3.4
If I divide .34 ÷ 10, I move the decimal place one place value to the left --> ._34
- If there is an empty place value in a decimal, I put a zero as a place holder --> .034
Adding Decimals
1. Line up the decimal places in your problem.
3 . 4 6
2 . 6
+ 0 . 3 4
2. Pull the decimal straight down into the answer.
3 . 4 6
2 . 6
+ 0 . 3 4
.
3. Add as you normally would.
3 . 4 6
2 . 6
+ 0 . 3 4
6 . 4 0
3 . 4 6
2 . 6
+ 0 . 3 4
2. Pull the decimal straight down into the answer.
3 . 4 6
2 . 6
+ 0 . 3 4
.
3. Add as you normally would.
3 . 4 6
2 . 6
+ 0 . 3 4
6 . 4 0
Subtracting Decimals
1. Line up the decimal places in your problem.
7 2 . 9 9
- 4 . 6 3
2. Pull the decimal straight down into the answer.
7 2 . 9 9
- 4 . 6 3
.
3. Subtract as you normally would, borrowing if necessary.
7 2 . 9 9
- 4 . 6 3
6 8 . 3 6
7 2 . 9 9
- 4 . 6 3
2. Pull the decimal straight down into the answer.
7 2 . 9 9
- 4 . 6 3
.
3. Subtract as you normally would, borrowing if necessary.
7 2 . 9 9
- 4 . 6 3
6 8 . 3 6
Multiplying Decimals
1. Set up the problem without worrying about decimal places.
2 5 . 3
x 2 . 2
2. Count the number of decimal places present in the problem.
2 5 . 3 2 decimal places in this problem.
x 2 . 2
3. Multiply as you would without decimals.
2 5 . 3
x 2 . 2
4 0 6
+ 4 0 6 0
4 4 6 6
4. Insert the number of decimal places from the original problem into the answer.
2 decimal places in this problem --> 4 4 . 6 6
2 5 . 3
x 2 . 2
2. Count the number of decimal places present in the problem.
2 5 . 3 2 decimal places in this problem.
x 2 . 2
3. Multiply as you would without decimals.
2 5 . 3
x 2 . 2
4 0 6
+ 4 0 6 0
4 4 6 6
4. Insert the number of decimal places from the original problem into the answer.
2 decimal places in this problem --> 4 4 . 6 6
Dividing Decimals
There are two types of division problems involving decimals. Decimals can be found in the divisor or in the dividend.
When a decimal is found in the divisor:
1. Make the decimal in the divisor into a whole number by moving the decimal to the right. 2. Move the decimal in the dividend the same number of places to the right. 3. Move the decimal in the dividend straight up into the quotient.
4. Divide as you normally would.
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If a decimal is found in the dividend, simply move the decimal straight up into the quotient and divide as you normally would.