Erica Nits 18 squares on Monday she knits seven more squares each day from Tuesday through Thursday how many squares does Erica on Friday

Monday: 18 squares

Tuesday: 18 + 7 = 25 squares

Wednesday:25 + 7 = 32 squares

Thursday: 32 + 7 = 39 squares

Friday: 39 + 7 = 46 squares.

This is called an arithmetic sequence. There is a faster way to do this with a formula.

The formula is a (n) = a1 + d (n-1), where

a1 is the first term (18 in this case),

d is the common difference, what you add or subtract to get the next number (7 in this case),

n is the term you want to find (5).

Plugging in our info into the equation,

a (n) = a1 + d (n-1)

a (5) = 18 + 7 (5-1)

a (5) = 18 + 28

a (5) = 46