Find the standard Deviation of 8,10,9,1

He ! a group of farmers planned to clean 80 acres of wheat per day to finish the work on schedule. right before the work started, they received a new piece of machinery that them clean 10 more acres per day than originally planned. as a result of increased productivity in the last day before the deadline they only had to clean 30 acres. how many acres of wheat did the group of farmers have to clean?

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

What is the solution for 6 - 7/8? explain the steps.