MultDec

Powers of 10

100

0.062 x 100 x 0.1 x 0.1

0.062

200

10⁵ x 0.0218

2180

300

(0.1)⁸

0.00000001

400

? x 0.0001 = 0.001729

17.29

500

0.00001 x ? = 0.0032001

320.01

Multiplying Decimals

100

0.06 x 2 x 0.004

0.00048

200

9.1 x 11.6

105.56

300

0.12 x 0.02323 = 

0.0027876

400

Skylar multiplied 4 copies of a number and got 0.0081. What number did Skylar multiply four copies of?

0.3

500

Alex writes down a decimal number.

Linus writes down one-tenth of Alex's number.

Theo writes down one-hundredth of Linus' number.

The product of all three numbers is 0.0000000008. What is Alex's number?

0.02

Multiplying with Zeros

100

Where is the decimal in the product?

30.1 x 3.02 = 90902

90.902

200

Where is the decimal point in the product?

1,683.5 x 0.0033 = 555555

5.55555

300

0.0125 x 0.0016 = 

0.00002

400

If I multiply 0.00063 by itself 11 times (so 0.00063 x 0.00063 x ... x 0.00063, but 11 times), how many digits will be to the right of the decimal point?

55

500

Mr. Cassin multiplies  (0.004)¹¹ x (0.05)¹¹. He had a lot of spare time on his hands.  

Not including trailing zeros, how many digits are after the decimal point in Mr. Cassin's product.

44

Missing digits

100

What are the values of A and B so that the equation is true and no number has trailing zeros?

0.A x 0.6 = 0.2B

A = 4

B = 4

200

What are the values of A and B so that the equation is true and no number has trailing zeros?

0.9 x 3.A = 2.B7

A = 3

B = 9

300

What are the values of A and B so that the equation is true and no number has trailing zeros?

2.A x 0.4 = 1.B2

A = 1

B = 3

400

What are the values of A and B so that the equation is true and no number has trailing zeros?

0.2 x 0.0A = 0.0B

A = 5

B = 1

500

What are the values of A and B so that the equation is true and no number has trailing zeros?

0.4 x 0.1A = 0.B6

A = 5

B = 0

Estimation

100

0.0312 x 4.961 is closest to which of the following:

0.15

1.5

0.15

200

Without calculating, which two of the following products are equal?
a) 0.792 x 0.712
b) 0.399 x 0.496
c) 1.96 x 0.404
d) 52.08 x 0.0038

b and d

300

Which of the following are greater?

a) 49.1 x 0.0682 OR 3.5

b) 0.0411 x 3.07 OR 0.12

c) 0.599 x 2.83 OR 20.9 x 0.0914

a) <

b) >

c) <

400

0.03125 x 64 is equal to what integer? Explain is estimation/rounding.

2

500

How many integers are between 4.21 x 0.387 and 9.5?

8