Mavis Marble uses her new Mitra Card ("The card that does the math for you" ) to buy material and yarn. She has been using it for 4 months. She just got a letter in the mail saying her account is now at -355.
"This can't be. My card says I have a credit of $240."
Mavis will need to compare her Mitra card charges with her payments.
Find the correct balance for her Mitra account.