How many Gb is in 269.140 MB

A Gb is the same as 1000 Mb. So one Mb is 0.001 Gb - that is one megabyte is 1/1000 th of a Gb (gigabyte). So 1 Mb = 0.001Gb. So 269Mb = 0.269 Gb.
And so 269.140Mb= 0.269140Gb. (which is very approximately one quarter of a Gb.