Algebra: Decimal numbers, power of 10, rounding

Decimal numbers are written with digits before and after a dot. Example: 3.1415926 is a decimal number. They are a variation of fractions and are used in science and business to represent fractional values. This module discusses the definition, and operations on decimals such as addition, subtraction, multiplication, and division of decimals.


Decimals are related to powers of 10: the farther to the LEFT digits represent increasing powers of 10: tens, hundreds, thousands etc. The digits that go to the RIGHT, after the dot, represent negative powers of 10: tenTHS, hundredTHS, thousandTHS etc. Special lesson presents the scales in the Universe using the scientific notation: the size of proton, the size of atom, the Earth diameter, the distance to the moon, the Sun diameter, the speed of light, the distance to the nearest star, the Galaxy diameter and the observable universe diameter.

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