To find the decimal expansion of a fraction, we put the denominator in proportion to 100. One fraction we can do this for is 2/5:
5 x 20 = 100, so now our denominator is 100. Because we multiplied 5 by 20, we also have to multiply 2 by 20. This means that 2/5 is equal to 40/100. 40/100 is representative as 0.4.
3/9 as a decimal can convert to 33/99, which would give us 0.3333 as a repeating decimal.
7/8 as a decimal expansion would give us 0.875 because 100 divided by 8 is equal to 12.5 (which is representative of 1/8), and 12.5 x 7 is equal to 87.5. Because we multiplied 1/8 x 7, we get 7/8 which is less than a whole. Therefore, the only number to the left of the decimal point should be 0. Hence, we divide 87.5 by 100 and we get 0.875. That is our decimal conversion.
4/6 as a decimal expansion would be 0.6666. Why? Well, first we would divide 100 by 6 to get approximately 16.6666. Then, because this represents 1/6, we can multiply it by 4 to get 4/6, which equals about 66.6664. Again, 4/6 is not a whole number and is less than a whole number. Because of this, the only digit to the left of the decimal point would be 0. When we divide 66.6664 by 100, we get 0.6666 as a repeating decimal.
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