KUMO N Ages 5-7 over MATH fun GAMES GAMES Practice addition and subtraction by solving fun puzzles Practice addition and subtraction by solving fun puzzles 5+ 十 =5 If your child knows how to read and write numbers 1-30 and has started to show an interest in basic addition and subtraction,this workbook will help develop his or her calculation skills.Your child will also develop critical thinking skills as he or she uses math concepts to solve fun and challenging number puzzles.