What is bar notation?

Bar notation is a decimal with a repeated number with a line on top of the repeated number.

EX.) 4.23232323 would be 4.23 with a line over the 4.23.

another...

EX.) 5. 22222222222222 would be 5.22 with a line over the 5.22.

Last one ...

cut off after the second 7

put a line OVER the bolded 7

EX.) 7.907777777777 would be 7.9077 with a line over the 7.9077.

that is bar notation :)