Two Decimals Column Addition Quiz
Practice Decimal Addition - Test Your Skills
An online decimal addition calculation
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Rules of Decimals
Addition and Subtraction
Step 1: Line up the decimal points.
Step 2: Put in zeros as placeholders, if necessary.
Step 3: Add or subtract.
ExampleStep 1- Line up the decimal points.
2.345 + 1.5
Step 2 - Put in zeros as placeholders
2.345 + 1.500
Add or subtract
2.345 + 1.500 = 3.845
Multiplication
Step 1: Multiply the numbers ignoring the decimals.
Step 2: Add the number of decimal digits in the original numbers.
Step 3: Move the decimal the same number of places to the left in your answer.
Example3.2 x 0.41 = ?
Step 1 - Multiply ignoring the decimal points
32 x 41 = 1312
Step 2 - Add the number of decimal digits in each of the original numbers: 3.2 has one decimal digit, and 0.41 has two decimal digits.
Therefore, the answer will have a total of three decimal digits
Step 3 - Move the decimal the same number of places to the left in your answer
1312 will become 1.312
Division
Step 1: Shift the decimal to the right to make the divisor (outside number) a whole number.
Step 2: Move the decimal of the dividend (inside number) the same number of places to the right as the divisor. Add zeros, if needed.
Step 3: Place the decimal point in your answer directly above the new decimal point in the dividend.
Decimal Fractions
To convert a number from fraction form to decimal form, simply divide the numerator (the top number) by the denominator (the bottom number) of the fraction.
Example:
5 / 8 = (Add as many zeros as needed) = 5.000 / 8 = .625
Converting a decimal to a fraction
To change a decimal to a fraction, determine the place value of the last number in the decimal. This becomes the denominator. The decimal number becomes the numerator. Then reduce your answer.
Example: .625 - the 5 is in the thousandths column, therefore,
.625 = 625 / 1000 = reduces to 5 / 8
Note: Your denominator will have the same number of zeros as there are decimal digits in the decimal number you started with - .625 has three decimal digits so the denominator will have three zeros.
Order of Operations
When more than one operation is to be performed in a problem, a specific order for solving the problem must be followed.
1. Solve anything in parentheses first
2. Solve anything with an exponent
Example: 52 - the 2 is the exponent; it means the number times itself that many times, so 52 = 5 x 5 = 25
3. Multiply/Divide from left to right in order
4. Add/Subtract from left to right in order