Let's get fancy and practice adding and subtracting decimals in the same word problem. Created by Sal Khan and Monterey Institute for Technology and Education.
Leo has $4,522.08 in his bank account. He deposits another $875.50 and then withdraws $300 in cash. How much is left in his account? So he's starting with $4,522.08. Let's write that down. $4,522.08. And then he deposits, or he adds, another $875.50. So he's going to add $875.50. When you deposit into an account, you're putting something into the account, or you're adding to the account. So after he adds that $875.50, what does he have? We go back to the penny spot, or we could view that as the hundredths. A penny is one hundredth of a dollar. Let me switch colors. We have 8 plus 0 is 8. 0 plus 5 is 5. We have the decimal right there. 2 plus 5 is 7. 2 plus 7 is 9. 5 plus 8 is 13. Put the 3 down here and regroup the 1, or carry the 1. 1 plus 4 is 5. So after the $875.50 deposit, he has $5,397.58. Then he withdraws $300 in cash, or he takes out $300, so we'll have to subtract that. So then he withdraws $300 and I just added some trailing zeroes after the decimal. $300 is the same thing as $300.00 and zero cents. And then we subtract. 8 minus 0 is 8. 5 minus 0 is 5. We have our decimal right there. 7 minus 0 is 7. 9 minus 0 is 9. 3 minus 3 is 0, and then 5 minus nothing here is 5. So he's the left with, in his account, $5,097.58.