Decimal Operations Review

Adding/Subtracting Decimals  IMPORTANT! Step 1: Set up the problem vertically!!! Line up the decimal points. Step 2: Add or subtract each column, starting at the right and working left. Step 3: Place the decimal point directly below the decimal points in the terms.

Adding/Subtracting Decimals Example 1:

Adding/Subtracting Decimals Example 2:

Adding/Subtracting Decimals Example 3: Ellen wanted to buy the following items. A DVD player for $49.95, a DVD holder for $19.95, and a personal stereo for $21.95. Does Ellen have enough money to buy all three items if she has $90 with her? How much change/how much money does she need?

Multiplying Decimals Step 1: Multiply as if they were whole numbers.  IMPORTANT! Step 1: Multiply as if they were whole numbers. Step 2: Count the number of decimal places in the terms being multiplied. Step 3: Place the decimal point in the product so there as many digits in the decimal part as you counted in the last step. Step 4 (if necessary): Place zeroes to the left end of the product to place the decimal point accurately?

Multiplying Decimals Example 1:

Multiplying Decimals Example 2:

Multiplying Decimals Example 3: Kelly earns $7.50 per hour at her babysitting job. On Sunday, she worked 7 hours. What were her total earnings for the day?

Dividing Decimals  IMPORTANT! Step 1: If the divisor is not a whole number, move the decimal point to the right to make it a whole number. Move the decimal point in the dividend the same number of places. Step 2: Divide as usual. Step 3: Put the decimal point directly above the decimal point in the dividend.

Dividing Fractions Example 1:

Dividing Fractions Example 2:

Dividing Decimals Example 3: There are 6.93 gallons of water in a tank. This water is to be transferred equally into 3 smaller containers. How much water will each container have?