Addition/Subtraction
Multiplication 1
Multiplication 2
Story Problems
Questions
100
2.6 + 4.9
7.5
100
3.8 x 5
19
or
19.0
100
2.7 x 2
5.4
100
Ganesh is making a scale model of the Space Needle in Seattle. The Space Needle is 605.0 feet tall. If the model is 1/100 the actual size of the Space Needle, how tall is the model?
6.05 feet.
100
Can you think of an example of decimals in the real world?
Radio stations... Money... Measuring things precisely... weight... etc!
200
13.3 + 14.2
27.5
200
12.3 x 7
86.1
200
3.31 x 9
29.79
200
Madison is in charge of buying meet for her company's annual picnic. She needs to buy enough meat to make 1,000 hamburgers. Each hamburger will weigh 0.25 pounds. How can Madison find how many pounds of hamburger meat to buy?
A) She should move the decimal 1 place to the left to buy 0.025 pounds
B) She should move the decimal 1 place to the right to buy 2.5 pounds.
C) She should move the decimal 2 places to the right to buy 25 pounds.
D) She should move the decimal 3 places to the right to buy 250 pounds.
D) She should move the decimal 3 places to the right to buy 250 pounds.
200
What is the most important part to adding and subtracting decimal? (Rule #1)
The most important thing is to keep your decimal points lined up.
300
4.32 + 3.26
7.58
300
5.36 x 13
69.68
300
2.47 x 24
59.28
300
Raina is making a shelf to store her collection of rocks and shells. She is using 5 pieces of wood that are each 3.25 feet long. How much wood will Raina use to make the shelf?
16.25 feet
300
Do decimals have to line up when multiplying?
No, you do not need to line up the decimal point
400
14.23 - 12.78
1.45
400
2.839 x 7
19.873
400
1.282 x 57
73.074
400
Mari and Rob want to figure out how much a rock that weighs 7 pounds on earth would weigh on Mars. They know they can multiply the amount the rock weighs on earth by 0.38 to find its weight on Mars. How much would this rock weigh on Mars?
2.66
400
Explain how to place the decimal point in the correct spot after multiplying a decimal by a whole number.
You may use this problem in your explanation!
0.35 x 6
You move the decimal all the way to the right. Count how many spots you had to move it, then move it that many spots back in the answer.
500
29.06 - 4.29
24.77
500
46.27 x 62
2868.74
500
15.45 x 33
509.85
500
Mandy , Jeremy, and Lily went to an amusement park. Mandy spend $16.25 at the amusement park. Jeremy spent $3.40 more than Mandy spent. Lily spend 2 times much money as Jeremy spent. How much money did Lily spend at the amusement park?
$39.30
500
Why is it important to put the decimal point in the right place?
Answers may vary - Mr. Z will check each board.