Write 5.11x10^3 in standard form

When i add money am i supposed to make it like this 7+12 or 7.00+12.00 because i got 19 dollars for my answer

Carmen begins her next painting on a rectangular canvas that is 82.7 cm long and has a area of 8,137.68 cm2. will the painting fit in a frame with an opening that is 82.7 cm long and 95 cm wide? explain

Andres wants to share 1/2 of his birthday cake with his friends. if he has 8 friends, how much of the cake will each friend recieve? draw a model to support your work (its ok if you cant)