I will admit that there is one type of worksheet that I used in the past and found relatively beneficial, although it had a different kind of flaw. For my Basic Math, Pre_Algebra, and Algebra classes, I had several books of "self_checking" worksheets. These worksheets had puns or puzzle questions at the top, and as the students worked the problems they were given some kind of code for choosing a letter to match that answer. If they worked the problems correctly, the letters eventually answered the pun or riddle. Students enjoyed these worksheets, but there are a couple problem areas even with these worksheets. Some students would get the answer to the riddle early and then work backward from letter to problem answer, so they weren't learning or practicing anything.
The heart shape is fantastically useful for teaching all sorts of mathematical problems, including geometry. Have your child cut out a heart shape from paper and use it to help them understand symmetry. How many lines of symmetry does a Heart Have? Help kids learn about patterns by using colored hearts or a series of Valentine's Day pictures. Introduce them to simple patterns; for instance red heart, green heart, red heart. From here you can make the patterns more complex by making them longer or including a higher degree of variation. Valentine's Day is a perfect opportunity for educating your child about many math problems; from simple arithmetic and word problems to patterning and geometry. There are many ideas to choose from that you're sure to find engaging and rewarding for both you and your child. So give them a try next Valentine's Day and see if your child will be struck by Cupid's arrow and feel the love for math.