One. first what you want to do you want to convert 20% into a decimal and a way to do that you need to move a decimal two times to the left. when finding the percent of something you will always move the decimal two times to left
now that you have your 20% into a decimal you will multiply 145 by .20
after you have multiply 245 by .20 you should have gotten 29.00
She has 29 pieces of yellow clothing
Sorry if this doesn't help, have a great day/night, hope it helps, and stay safe!