Hello! So, $1,000 is invested in the account. You lost 13% of that later on. To find out how much is left after that, multiply 1,000 by 87%. This is because although you have lost 13% of it, you still have 87% of it left. 100 - 13 is 87. 1,000 * 87% (0.87) is 870. So your statement is down to $870. However, you gain 13% of the current amount. To find out the amount in the account, add 1 to the rate in decimal form, and then multiply that by the amount in the statement. We add 1 to the rate when we're looking for total amount, because doing that will take you straight to the total amount and makes you less likely to make an error. 13% is 0.13 in decimal form. 1 + 0.13 is 1.13. 870 * 1.13 is 983.1. There. The value of your account is $983.10.