I still remember the fun our family had using mental math. Do you have any that we could use at the dinner table? - Mealtime Math
Answer: Children are not always taught how to use mental math in school. However, it is very handy both for finding exact answers and in everyday estimation. It's also fun for children to practice at the dinner table and on trips. You can begin by having them work with numbers that have zeros. For example, to add 200 + 300 + 40, they would say: "Two hundred and 300 is 500, and 40 more is 540." To multiply 7 x 300, they can say: "Seven times three is 21. Add on two zeros, and you get 2,100."
Teach your children to begin on the left when adding numbers. To add 24 + 32 using mental math, they would say: "Twenty and 30 is 50. Four and two is six. Fifty and six is 56." They can also go from left to right when multiplying large numbers. To multiply 74 x 8, they would say: "Eight times 70 is 560. Eight times four is 32. Five hundred sixty and 32 is 592."
There are diverse ways to solve most mental math problems. Parents will profit from reading books on the topic. Dale Seymour Publications has "Mental Math" books for the primary grades through junior high.