Simplify the following. Leave answer as a power.811  815

Decide whether or not the set is closed under addition.{n  N: n  53}

Decide which property of addition is illustrated.(6 + 4) + 1 = 6 + (4 + 1)

Round the number to the place value indicated.

Find the missing numbers.

Decide which property of addition is illustrated.(1 + 8) + 8 = (8 + 1) + 8

Solve the problem.Jamie is planning to start her own business. She has saved $1100 for this purpose. She estimates a cost of $880 for materials and $480 for advertising. By how much money is she falling short?

Solve the problem.Jake is doing some chores for his father. He takes 50 minutes to clean the garage, 40 minutes to mow the lawn, and 55 minutes to trim the hedges. How much time, expressed in hours and minutes, did he spend working?

Find, if possible, the whole number that makes the equation true.35 = 21 + 2  

State the property that is illustrated.(4 + 6)(9 + 15) = (4 + 6)9 + (4 + 6)15