Multiplying by 6, 7, 8, and 9 using only your hands

Multiplying by 11 (example: 11×32)

The butterfly method for adding and subtracting fractions

#2 Learning the nine times table

Multiplying large numbers in your head

Multiplying large numbers in your head

Arithmetic - ( Basic operations )

There are 4 basic operations. The graphic organizer below shows what these operations are along with some other important terms.

Basic operations key terms explained

The actual age of the universe

The discovery of the expansion of the universe achieved by the astronomer Edwin Hubble at 1929, was based on the red shift of the faraway galaxies, red shift occurs when an object is receding far away from an observer, and so the object´s light wave left behind it get elongated, light waves when elongated are shifted to red Fig.1. When Hubble discovered that the light received from the galaxies located farther away from the Earth, is more red shifted, that means the farther galaxies receding speeds from the Earth are higher than the nearby ones, which means that as the farthest galaxies are speeding up⁽¹⁾, the whole universe containing them is receding from us, or by another way, it is expanding, but what is the relation between this and the age of the universe?

Fig. 1 ⁽²⁾