These tricks can be used by generations to come also regardless of how the technology grows. Since so much has developed, we can even see these tips as advice that our grandmother gave us.

We have jotted down al list of things you probably learnt as a child but have completely forgotten about them. Re-learnt them as they can be very useful even now.

1. Know the number of days in a month

Make a fist, and start counting the months by knuckles. Each knuckle bump and gap is a separate month. If you count on one hand, then, after reaching the end, start again with the knuckles of the index finger.

If the month is on the knuckle bump, there are 31 days. If it’s on the gap — 30 or less.

2. Know if the moon is waxing or waning

To teach your child how to determine the moon phase, use the shape of the letters D, O, and C. The full moon is O, the first quarter is D, and the third is C.

3. Determine the time left before sunset

Keep your fingers together, and reach your hand out so that the sun “lies” on your index finger. Now count the number of fingers to the horizon line. Each of the fingers represents approximately 15 minutes until sunset.

4. Length

If you need to approximately measure an object but there’s no ruler at hand, you can use the fingers of one hand. In accordance with the average human proportions, the distance between the tips of the thumb and forefinger is about 18 cm (7″), and the distance between the thumb and little finger is about 20 cm (7.87″).

Of course, this method isn’t absolutely accurate because each of us has a different hand size. Yet it can be useful if you need to measure a large object with a small ruler: just measure the distance between your fingers in advance.

5. Know the degrees of an angle

Spread your fingers as much as possible, and put your palm on a surface, the angle of which you want to measure. The little finger should lie on the bottom side: it means 0°. The angle between the thumb and the little finger will be 90°, the angles between the little finger and other fingers are, respectively, 30°, 45°, and 60°.

6. Multiplication on fingers

Usually, children quickly remember the multiplication of small numbers, but they have difficulties with the numbers 6, 7, 8, and 9. To help your child with this, teach them a simple trick.

Turn your palms to your face. Number each finger, starting with the little finger, from 6 to 10. Now, for example, to multiply 7 by 8, connect finger #7 on the left hand with finger #8 on the right.

The number of fingers at the bottom, counting along with the connected ones, means tens (we got 5 of them). As for the fingers located at the top, you need to multiply them among themselves — they mean units (in our case, multiply 3 by 2). Answer: 7×8 = 56. In this way, you can quickly multiply by 6, 7, and 8.

7. Check battery quality

There is an easy way to figure out if your battery is in a good condition or a bad condition. Simply elevate two batteries side by side above a table. Make sure they are at least one to two centimeters above the table. Just drop them and you will find out – the one that bounces is the one that is empty.