Charlotte went shopping and spent 86 dollars and 97 cents. She spent 𝑏 dollars on books and 48 dollars and 52 cents on CDs. Using the equation 86.97 is equal to 𝑏 plus 48.52, determine the amount that she spent on books.
We need to solve the equation 86.97 is equal to 𝑏 plus 48.52 to calculate the value of 𝑏, which is the amount that Charlotte spent on books. 48.52 is the amount that Charlotte spent on CDs. And, 86.97 dollars is the amount that she spent in total. In order to solve this equation, we need to subtract 48.52 from both sides of the equation. On the right-hand side, the 48.52s cancel. And on the left-hand side, we have 86.97 minus 48.52.
We can calculate this using column subtraction. In the hundredths column, we have seven minus two. This is equal to five. In the tenths column, we have nine minus five. This is equal to four. We must keep the decimal point in the same position. We cannot subtract eight from six without getting a negative number, so we need to go to the tens column and borrow a one. In the units column, we then have 16 minus eight. This is equal to eight. Seven minus four in the tens column gives us three. 86.97 minus 48.52 is equal to 38.45. As 𝑏 is equal to 38.45, the amount of money that Charlotte spent on books is 38 dollars and 45 cents.