To learn to add, subtract and dial beads, you must first remember the formula. The original formula in the abacus mental arithmetic textbook is simple and boring, and many children can't remember it. Some children remember it for a while, but soon forget it. In view of this situation, in teaching, I often organize children to compose rhymes and perform while reading. For example, when learning complement addition and subtraction, I will make up rhymes with children:

Add one, please dial double nine, we are all good friends;

Add two, please dial double eight, laugh when you are happy;

Add three, please dial double seven, sometimes you will be angry;

Add four, please dial double six, and jump if you are happy.

If you subtract one, please dial double nine and sing like a lark;

If you subtract two, please dial double eight, don't delay too much;

If you subtract three, please dial double seven and queue up neatly to do exercises;

If you subtract four, please dial double six. Don't sleep late in the morning.

Because teachers actively mobilize children to create children's songs with teachers, children like to learn and perform, so they remember the formula firmly, thus further improving their understanding and memory ability.

Complement addition and subtraction: in overtime, this file should be over ten, plus a complement;

When the time is reduced, the file is not reduced enough, and it will be reduced by returning a complement.

Finger flick: enter a pair of points and return a pair of points.

Ball-pulling formula

1, plus one: enter a pair of nines, minus one: return a pair of nines.

Add two: enter a pair of eights and subtract two: return a pair of eights.

Add three: enter a pair of sevens and subtract three: return a pair of sevens.

Add four: enter a pair of six minus four: return a pair of six.

Plus five: one, five minus five: five minus five.

2. Add six: forward one four (4+6) and subtract six: backward one four (10-6).

Add seven: enter three (3\4+7) and subtract seven: retreat one and go up three (10 \1-7).

Add eight: one into two (2\3\4+8) and subtract eight: one into two (10 \1\12-8).

Add nine: enter the next (1\2\3\4+9) and subtract nine: return to the previous (10 \1\12 \13).

Direct increase or decrease of forward and backward positions: overtime does not help to count away, and time reduction does not help to count back.

Finger play: two-handed dial, two-handed dial.