Two-thirds in decimal format is 0.667 when rounded to three decimals. In reality, the decimal format of 2/3 is 0.666... The number is followed by an ellipses, to indicate that six repeats infinitely.
To convert a fraction into decimal format, the denominator should be changed to 10. In the above example, the denominator is three. To change it to ten, it is multiplied by 3.333 when rounded to three decimal places. To change 2/3 into a decimal, first multiply two and three by 3.333. Three multiplied by 3.333 is equal to 10, and two multiplied by 3.333 is equal to 6.667 when rounded to three decimals. Thus, the fraction becomes 6.667/10. Dividing 6.667 by 10 yields 0.667.