Add, Sub, Multiply and Divide Decimal Word Problems

You need to line up the decimal points of the numbers in your problem when you are performing which mathematical operations?

• Adding

• Multiplying

• Subtracting

• Dividing

There is no need to line up the decimal points of the numbers in your problem when you are performing which operations?

• Adding

• Multiplying

• Subtracting

• Dividing

When estimating the answer to a multiplication operation similar to this one, an effective strategy is to . . .

• Mentally round the numbers to their greatest place value and multiply using basic math facts, adjusting the answer with the appropriate number of zeroes.

• Jot down the first two digits of each number and multiply them, then add the right number of zeroes.

• Do the math with paper-and-pencil, get the exact answer, then round that to the greatest place value.

• Pick off the first digit of each number, then multiply them. Add the proper number of zeroes.

When the divisor in your long division problem has decimal digits, you must remember to . . .

• Move the decimal to the right in both the divisor and the dividend enough places to make the divisor a whole number.

• Round the divisor up so that it is a whole number, then divide like always.

• Move the decimal in the dividend so that that number now has the same number of decimal digits.

• Be sure to move the decimal in the dividend and the divisor to the left enough so that that both numbers have only significant digits that are decimal digits.

One pound of strawberries cost $4.26. Anna buys 5 pounds of strawberries. How much will the strawberries cost?

• $2,130

• $21.30

• $21.03

• None of the above

Mrs. Barnhart had students who had taken a test. One of the students score .79. The other scored .98. What was the difference between the two students scores?

• 200

• 1.77

• 1.9

• .19

Emily bought the following amounts of fruit at a fruit stand:

0.75 pounds of grapes

0.5 pounds of bananas

1.25 pounds of apples

How much did her fruit weigh altogether?

• 0.25 pounds

• 2.05 pounds

• 2.5 pounds

• 25.0 pounds

On three different days at her job, Payton earned $27.50, $33, and $49.75. The desk she wants for her computer costs $100. If she buys the desk, how much money will she have left over?

• 209

• 9

• 102.50

• 10.25

On three different days at her job, Payton earned $27.50, $33, and $49.75. The desk she wants for her computer costs $100. If she buys the desk, how much money will she have left over?

• 209

• 9

• 102.50

• 10.25

On Tuesday 57 people rent skates at Stardust Skate Center. It costs $2.59 to rent skates. How much money does the rink make in skate rentals on Tuesday?

• $259.00

• $1,476.30

• $147.63

• $2590.00