This article is about teaching mental math tricks for addition to the primary school child. Almost every child starts by counting on her fingers. This is easy to do when the sum is less than ten. It starts to get confusing when the total is more than ten. After learning these tricks, the child should be a math wizard!
get the basics
The trick to perform mental math quickly by understanding the idea of groups of ten. The first thing to do is to put ten pencils on the table. Move one pencil aside; now you have a group of nine pencils and a pencil group. Ask your child what is the answer to the nine plus one. Write it out mathematically
9 + 1 = 10
Carry on this way for eight plus two, seven plus three and so on until the child knows all the combinations that make up a group of ten . The next step is to commit them to memory. One way to do this is in writing similar to this:
7 + ___ = 10
____ + 8 = 10
10-6 = ____
Another interesting way through the game. Take out a normal pack of cards. Remove all the tens and picture cards, leaving only the Aces to the nines. Shuffle the cards and place the deck face down on the table. Turns to look over the top card. Let’s say it’s three, the other person must call the number that would give a total of ten – in this case, the number seven. Your points for correct answers. The first to reach twenty points wins. Play this several times a day and your child will soon remember all groups of ten.
A variation of this game is based on the memory game. Spread out the cards face down on the table. Exchanging lifting up two cards at once. If the total of ten, you collect cards and take another turn. The player with the most cards at the end of the game wins.
less than twenty
Now the child is ready to mentally add numbers to a total of more than ten but less than twenty. For example, add seven and eight. They already know that the seven and three make ten. Split number eight in three and five. Add three to seven make ten. You are left with five so that the total is fifteen. Here’s the trick written out mathematically
7 + 8 = 7 + 3 + 5 = 10 + 5 = 15
It may seem complicated at first, but your child will get an idea very quickly . In practice, use the cards again. This time take two cards at the time of the stack. The first to add a number of works right.
When the child has mastered the first two tricks, it’s time to learn how to add larger numbers. Here’s what to do to add twenty-five and seventeen
25 + 17
= 20 + 5 + 10 + 7
= 30 + 5 + 5 + 2
= 30 + 10 + 2
It takes a little getting used to, but by using the idea of groups of ten, the child should learn this mental math tricks in no time!