Finger mental arithmetic formula table is jingling.
China children have their own experience in this respect, because we have mental arithmetic, verbal arithmetic and abacus mental arithmetic. Let's look at the mental arithmetic formula table.
Finger mental arithmetic formula table jingles 1 mental arithmetic formula table jingles are:
1, mental arithmetic addition formula table: with or without carry, with carry, direct addition, with five, with ten and with five.
2, mental arithmetic subtraction formula table Dangdang: do not abdicate, abdicate. Subtract, directly subtract, break five subtract, abdicate subtract, retreat ten make up five subtract.
3. The formula table of division and retreat is tinkling: division and retreat-next one, division and retreat-next two, division and retreat-next three, division and retreat-next four, division and retreat-next six, division and retreat-next seven, division and retreat-next eight and next nine.
4. The nine-mouth formula of the division quotient is a jingle: see no divide into nine, see binary nine, see three divide into nine, see four divide into nine, see five divide into nine, see six divide into nine, see seven divide into nine, see eight divide into nine and nine divide into nine.
Abacus mental arithmetic addition formula table:
One up one, two up two, three up three, four up four, five up five, six up six, seven up seven, eight up eight, nine up nine; Two five to three, three five to two and four five to one.
One to nine, two to eight, three to seven, four to six, five to five, six to four, seven to three, eight to two, nine to one.
Abacus mental arithmetic subtraction formula table:
One, two, two, three, three, four, five, six, seven, seven, eight, nine, nine; One on four to five, two on three to five, three on two to five, four on one to five; One retreats nine, two retreats eight, three retreats seven, four retreats six, five retreats five, six retreats four, eight retreats two, nine retreats one.
Finger mental arithmetic formula table jingle 2 mental arithmetic addition formula table jingle: add without carry, add with carry, add directly, add with five, add with ten and add with five.
1, directly reduce if you don't abdicate.
2, abacus mental arithmetic division nine belongs to the formula, every one into one, every two into two, every three into three, every four into four, every five into five, every six into six, every seven into seven, every eight into eight, every nine into nine. The formula for returning business by abacus mental arithmetic division is nothing more than returning one, two, three, four, five, six, seven, eight and nine.
3. When the sum of ten plus two numbers is more than 10, and there are not enough beads in this gear, dial the complement of the added number in this gear and 1 in the left gear. This method is called 10 addition.
Expansion: Sometimes, a simple formula or phrase can help children remember theorems and formulas in mathematics more vividly. For addition and subtraction within 100 (pen calculation), attention should be paid to pen addition, and the same digits should be aligned;
Start with a single digit. If one digit is full of 10, go up to ten digits. The abdication subtraction should be kept in mind, starting from the unit; Who is not enough to retire, don't forget to add ten to the standard; If the interval is 1, it is best to remember that 0 becomes 10.
Nine formulas of abacus mental arithmetic division quotient;
See no score 9 1, no score 92, no score 93, no score 94, no score 95, no score 96, no score 97, no score 98 and no score 99.
How to learn abacus mental arithmetic
1, mental arithmetic must master the method of dialing beads. Whether the method of dialing beads is correct or not will directly affect the speed and accuracy of mental arithmetic.
2. Practice frequently and master basic arithmetic.
Finger mental arithmetic formula table Ding Dong 3 Make fists with both hands, palms inward, and the interval between the two fists should not be too wide. Raise your arms horizontally, with your fingers starting from the index finger of your right hand and the index finger sticking out to represent1; The middle finger extension represents 2; The extension of the ring finger represents 3; The little finger extends to represent 4; Four fingers retracted, thumb extended, representing 5; When you count to 9,
Retract the extended five fingers, and the left index finger represents10; 1 1? The index finger of the left hand does not move, and the index finger of the right hand extends again, and then goes down to19 in turn;
Take back the five fingers of the right hand and the middle finger of the left hand is 20. On the count of 49, retract the fingers of the right hand and the left hand, the thumb of the left hand represents 50, and so on to 100.
Elementary: addition and subtraction within 100.
Preparation: Before reading the following formula and playing related finger games, the teacher needs to give the password "Clear", and the children will clap their hands immediately, then hold their fists on their chests and concentrate on getting ready. (Note: the palms are inward, and the distance between the two fists is based on the convenience of the fingers, not too close or too far. )
First, the finger positioning formula
I have a pair of hands, representing ninety-nine; Set the left hand to ten, and I can count to ninety; Pose your right hand and count from one to nine; It's convenient to add and subtract, so don't worry about calculation.
Second, the hand index formula
The index finger extends "L" and the middle finger extends "2";
The ring finger is "3" and the little finger is "4";
Four fingers and a thumb, the thumb is "5" to remember;
Then extend the index finger to the little finger, and "6", "7", "8" and "9" are arranged in numbers.
Third, the right hand points out the exercise formula.
Take the lead, two tigers contend, in a few words, the four seas are at home, and the grain is abundant.
Six animals are thriving, and the eight immortals are crossing the sea, and nine Niu Yi hairs are urgent.
A word nine, two dragons playing with pearls, three pillars separated, surrounded by enemies, the grain is abundant.
Six gods without a master, seven ups and downs, exquisite, nine Niu Yi hairs, perfect.
(Note: When reading "urgent" or "perfect", make a fist in your right hand and put "1" in your left hand, indicating carry. )
Fourth, the left hand points out the exercise formula.
Ten, twenty, thirty, forty; Fifty,
Sixty, seventy, eighty, ninety, one hundred.
(Note: When reading "100", clap your hands, and then put your fist on your chest. )
Five, two-handed counting exercises
15、23、46、99、58、73、6 1 ……
(Note: Choose the number according to the cognitive level of children of all ages. )
Six, addition exercises
Note: When doing addition exercises, such as "3+5", the right hand will give out "3" first, and the process of "+5" is: say "plus 1" in your mouth and extend your little finger; Say "plus 2" in your mouth and stretch out your thumb with four fingers (note that the thumb only represents "1" in the process of pointing out, and the thumb is only regarded as "5" when deciding the number);
Read "plus 3" in your mouth and stretch out your index finger; Read "plus 4" in your mouth and stretch out your middle finger; Say "plus 5" in your mouth and extend your ring finger. At this time, counting began, only the little finger of the right hand did not open, and the result was "8".