PlosMathLearning

Decimals

Decimals


Practice Quiz

Multiplying with Decimals

  When multiplying decimal numbers you can first treat them like whole numbers, then place the decimal point in its correct place in the answer by finding the total number of decimal places of all numbers in the product.

 

Example 1: Evaluate 2.35 x 2.4

 

We know that 235 x 24 = 5640

 

Since 2.35 has two digits after the decimal point and 2.4 has one digit after the decimal point, the product has (2 + 1 = 3) three digits after the decimal point.

 

Answer: 2.35 x 2.4 = 5.640

Dividing with Decimals

When dividing decimals you can first make the divisor (the number you are dividing by) a whole number by multiplying by the appropriate power of 10. You should multiply both the numerator and denominator by the same power of 10.

 

Example: Evaluate 1.50.05

 

Solution: 1.50.05 x 100100

 

Now, we have 1505

 

Answer = 50

Adding or subtracting Decimals


When you are adding or subtracting decimals, place the decimal points in one vertical position, one beneath the other.

 

Example 1: Evaluate 3.45 + 3.2 + 1.24

   3.45
   3.20
 +1.24
   7.89

 

Example 2: Evaluate 8.5 - 2.47

  - 8.50
  -2.47
   6.03





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