There are several standard exercises which train students to convert percentages, decimals and fractions. Converting percentage to decimals for example is actually as simple as moving the decimal point two places to the left and losing the percent sign "%." Thus 89% is equal to 0.89. Expressed in fraction, that would be 89/100. When you drill kids to do this often enough, they learn to do conversion almost instinctively.
I recommend getting one of these books when you first begin homeschooling and use it as a reference throughout your homeschool journey. Regardless of how long you homeschool, you'll always have doubts and questions about how your child is performing.A scope and sequence book can put your mind at ease.
Or you can usually find textbooks and workbooks at the public library, where you can also copy any worksheets that you want to use.
However, caution must be taken into account when review is repeatedly covered in your classroom. You do not want your students to become bored or frustrated with the repetition.