How do you write #3/7# as a decimal?

2 Answers
Mar 1, 2016

#3/7 = 0.bar(428571)#

Explanation:

Long divide #3# by #7# to find #3/7 = 0.bar(428571)#

enter image source here

Long divide until the remainder repeats. In this case we find the remainder #3#, repeating the number we started with.

This show us that the pattern #428571# will repeat, so we write:

#3/7 = 0.bar(428571)#

or with dots:

#3/7 = 0.dot(4)2857dot(1)#

Mar 1, 2016

#0.bar(428571)#

Explanation:

The sevenths' decimals have an interesting property: they repeat with the same numbers, in the same order.

The decimals of any fraction with denominator #7# have the digits in order:

#1,4,2,8,5,7#

For example,

#1/7=0. color(red)(142857)color(green)(142857)color(blue)(142857)...=0.bar(152857)#

#2/7# follows the same pattern, except for that it starts with the next highest number in the series #1,4,2,8,5,7#, which is #2#. The decimal then goes in order, up until #7#, then goes to #1,4# at the beginning and beings the series again:

#2/7=0. color(red)(285714)color(green)(285714)color(blue)(285714)...=0.bar(285714)#

#3/7# behaves similarly, except for that it begins with the next highest number -- #4#.

#3/7=0. color(red)428571color(green)428571color(blue)425871 ... = 0.bar(428571)#

The series continues:

#4/7=0.bar571428#

#5/7=0.bar714285#

#6/7=0.bar857142#