How to calculate quickly with your hands

Children instinctively use their fingers to do arithmetic, and this is natural. There is a reason why we call the numbers "digits". Hands and fingers are very useful calculators that never need batteries. You can use your hands to do addition, subtraction and multiplication . Your hands can also tell you the number of days of each month.

one

To count to 99, give the fingers on the right a value of 1, and the right thumb a value of 5. Let the fingers on the left have a value of 10 each and the left thumb is worth 50. This makes it is possible to represent any number from 0 to 99 in the hands. Start counting with both hands on the fists to represent zero. Start by extending the fingers of the right hand one at a time to count from 1 to 9, going from 4 to 5 putting the fingers in and extending the thumb. Then put one finger to the left up and all the right hand in a fist, to represent the 10. Continue in this way until all the figures extend to represent 99.

two

To add two numbers, start with the first number in both hands. Add the second number at the top of the first number. Sometimes this is easy, for example, the addition of 13 to 15 requires that it represent 13, one extended left finger and three extended right fingers, and add 15 more, extending the right thumb and one finger to the left. Now there are two fingers on the left extended, as well as three fingers on the right and the right thumb. This equals 28, the sum of 13 and 15. Sometimes, the process is more complicated, for example, when you might have to carry a number or recognize that 3 fingers plus 3 fingers, is a finger and a thumb.

3

To multiply a figure by nine, keep your hands in front of you with all your fingers and your thumb extended and the backs of your hands in front of you. To multiply 9 X 7, count from the left, starting with the little finger of the left hand, seven fingers until you reach your index finger of the right hand and fold it down. Read the answer by counting the fingers on each side of the bent finger: 63. To multiply 9 X 3. Lift all the fingers, start counting on the little finger of the left hand and count three fingers until you reach the middle finger of the hand left and double down. Count the fingers on both sides of the bent finger to get 27. Unfortunately, this only works to multiply by 9, to remember the table of 9.

4

Remember how many days you have each month, counting the knuckles and depressions in your left fist. January is the first knuckle, which represents a long month. February is the depression between the first two knuckles, which represents a short month, March is the next articulation, a long month. Continue until the last knuckle, which is July. Return to the first phalanx for August, a long month and continue.

• Keep your fist loose and do not insist that all fingers extend the same amount.
• Most months are 31 or 30 days. February has 28 days, except in leap years every four years when it has 29 days.