Brianna received a $398 paycheck last week and then spent $49 of her earnings on a gift. how much of her earnings remained after she bought the gift?

Can someone me with this problem i don't understand i need

Acyclist bike x distance at 10 miles per hour .and returns over the same path at 8 miles per hour. what is the cyclist average rate for the round trip in miles per hour ?

What is 100,000 times 1/100,000, using the standard method of multiplication? write the answer as 10 to a power.