8 Times the sum of a number and 3​

This question is asking you to write the algebraic expression for "five times the sum of a number and 8).  Basically it is saying take a number (x) and add 8 to it. When we add, the answer is the sum.  

So the first part of the expression is (x + 8)

Then multiply that sum by 5

So our answer is 5(x+8)

add all the numbers and check the ones place.

the answer is 486. as the ones place is more than 4, the estimation will be the next 10 ie, 490

you can first factor out the n to get n(1+5). we know that 1+5 is 6, so we just have 6n.