Despite the time elapsed these are still valid, but many people have forgotten or simply have been fading from collective knowledge. Keep reading and re discover these incredible tricks that will be of great help.
Know the number of days of each month
With the closed fist counts the months by the knuckles. Each knuckle and each cleft between them represents a month. If the month falls on knuckle has 31 days, if it falls into a cleft has 30 or less.
Determine the time before sunset
Put your fingers together and stretch your hand so that the sun is on your index finger. Count the number of fingers to the horizon; each finger represents an approximate 15 minutes for the sunset.
Waxing crescent moon?
To know in which phase the moon compares it with the letters D, C, and O. Moon D is increasing, O is full Moon and C is waning.
Nemotechnique to learn Roman numerals
Use the following phrase: LaCa De Mamá. The letters L, C, D, M represent the numbers 50, 100, 150, and 200 respectively.
Check the charge of a battery
Raise the battery to one or two centimeters on a table and let it fall; if it staggers and falls it has no load.
The Nine Table with Hands
Put your hands with your palms towards you. Assign to each finger of the left hand a number, from 1 to 5, starting with the little finger; and from 6 to 10 to each finger of the right hand starting with the thumb. Now, to multiply, for example, 9 × 7, lower the assigned finger with the number 7; the number of fingers remaining to the left of that finger will be tens, and the number of fingers to the right units. In the example, 9 × 7 = 63.