Answer:
52 minutes
Step-by-step explanation:
it takes him 13 minutes to complete 5 so if he wants to do 20 problems do 20 divided by 5 (4) then do 13 times 4=52
64 x 10 = 640
Easier way to simplify :
64 x 1 = 64 and then put the 0 at the end which = 640
Answer:
20
23 is between 20 and 30, but it's closer to 20. So 23 is rounded down to 20.