Erica knits 18 squares on monday. She knits 7 more squares each day from tuseday to thursday. How many squares did Erica knit in all by the end of the day on thursday
Erica knits 18 squares on Monday. She knits Tuesday through Thursday which is 3 days. She knits 7 squares each day making it 21 total squares these days. For the whole week, she has knitted 18 + 21 = 39.
