Cook with your kids. When they cook with you they learn a valuable life skill, they learn fractions, and they learn the importance of following directions. When you are baking deliberately misplace a certain measuring cup you’ll need so you can teach fractions. If the recipe calls for a 1/2 cup then use a 1/4 cup instead and teach that two 1/4 cups equal a half. Teach teaspoons and tablespoons also.