Question

guy's plz help me answer these 8 questions ! plz answer all of them !


1. 791.3 × 0.06 =


2. 117.6 ÷ 2.1 =


3. 4 × 0.002 =


4. 3.639 ÷ 0.03 =


5. 0.48 ÷ 120 =


6. Adrian said that 21.8 × 1.9 equals 41.42.


Is Adrian's answer reasonable?


7. Abby said that 22.47 ÷ 2.1 equals 0.107.


Is Abby's answer reasonable?


8.Mary solved this problem.


Robert bought 5 packages of rubber bands. He paid $0.69 for each package. How much did Robert pay for the rubber bands?


Mary thought the answer was $345.


Is Mary's answer reasonable?



thank you so much my frnds !

Answer 1

1. 791.3 x 0.06 = 7913 x 6 x 10^(-3)
= 47478 x 10^(-3)
= 47.478


2.117.6/2.1
= 1176/21
=56


3. 4 x 0.002
= 4 x 2 x 10^(-3)
= 8 x 10^(-3)
= 0.008

4. 3.639/0.03
= [3636/3] x [10^(-3)/10^(-2)]
= 1212 x 10^(-3-(-2))
= 1212 x 10^(-1)
= 121.2



5.

0.48/120
= [48/100]/120
= 48/12000
= (48/12)x 10^(-3)
= 4 x 10^(-3)
= 0.004

6.
21.8 × 1.9 = 41.42 ?

21.8 x 1.9
= 218 x 19 x 10^(-2)
= 4142 x 10^(-2)
= 41.42
TRUE

7.
22.47 ÷ 2.1 = 0.107 ?

22.47/2.1
= [2247/21] x [10^(-2)/10^(-1)]
= 107 x 10^(-2-(-1))
= 107 x 10^(-1)
= 10.7
=/= Not equal to 0.107 (so FALSE)

8.
Robert bought 5 packages of rubber bands. He paid $0.69 for each package. How much did Robert pay for the rubber bands?

Cost of 5 package of Rubber bands = No. of packages of Rubber band x Cost of each Rubber band package

= 5 x 0.69
= 5 x 69 x 10^(-2)
= 345 x 10^(-2)
= 3.45$

Mary thought the answer was $345
it's not 345 $ instead it is 3.45$