Pocket this quick mental calculation as well as this extremely accurate timing tip.
Since ancient times, when modern technology was not yet developed, our forefathers knew how to calculate, memorize or determine time… with very simple and interesting tips.
Let’s explore very useful and simple tips below!
In the absence of timekeeping devices such as watches or cell phones, observing the Sun is a familiar way of determining the time of day.
You can use your hands to determine when the Sun sets.
Since a long time ago, people have discovered a way to determine when the sun is going down by the method of … using hands to measure time.
Specifically, at sunset, close your hand and raise it towards the Sun so that the edge of your little finger coincides with the horizon. When the edge of the upper index finger “touches” the Sun (as pictured above) it means that the Sun will set in just an hour. Each of your fingers now represents 15 minutes before nightfall.
Tips to help determine whether the Moon is waning or rounding.
Have you ever looked at the image of the waning moon and wondered if the moon is in the waning phase or is it getting fuller? Do not rush to look up the Internet because there is a very simple definite trick.
Remember these 3 letters carefully: C, O and D!
The letter O is the image of the Full Moon. The letter C shows that the Moon is in the waning phase, and the D-shaped moon means that it is in the rounding phase.
Simple tips for remembering Roman numerals.
It seems that anyone can remember the symbols I, V, and X which are Roman numerals that represent 1, 5 and 10 respectively. But can you confidently remember the hundreds and thousands digits written like how?
There is a very interesting trick to help you “want to forget” this Roman numeral system!
Remember the following English sentence:
“My Dear Cat Loves Xtra Vitamins Intensely”.
The first letters of each word in the sentence represent the Roman numerals in descending order: M (1,000), D (500), C (100), L (50), X (10), V (5), I (1).
Place your hand so that your little finger is parallel to the edge of any angle you want to measure, and that convention is 0°.
Extend your hand fully and place it on the surface or angle you want to measure. Place your hand so that your little finger is parallel to the edge of any angle you want to measure, and that convention is 0°.
Then, the angle formed between the thumb and little finger will be approximately 90°, and the index, middle, and pinky fingers will form an angle of approximately 60°, 45°, and 30°, respectively, with the little finger.
Normally, we can easily memorize multiplications with small numbers, but multiplications with numbers from 6, 7 … and up make many people confused.
Mental calculation using 10 fingers.
There is a very simple trick that helps us do mental math when “forgetting the multiplication table” by using our fingers. Here is how this 10-finger mental calculation is applied to multiplications from 6 to 10.
For example, do the multiplication 7×8=?
Example of 7×8 multiplication.