26. sunnyday elementary school is having its annual read-a-thon. the third graders have read 573 books so far. their goal is to read more than 900 books. what is the least number of books they need to read to reach their goal? explain.

327 books are needed to be read.

Step-by-step explanation:

Let the 3rd graders have to read the total number of books = x

Since they have read 573 books s far so number of books left to read = (x - 573)

If x = 900

then minimum number of books to be read by 3rd graders = 900 - 573

= 327 books

Therefore, 327 books are needed to be read.

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb