4= 4/1 as a fraction, and you must make 2 3/5 into a improper fraction, to do that you must multiply the denominator times the whole number and add the numerator so 5x2=10 and 10+3=13 so the numerator now turns into 13 and the denominator stays the same (5) so now you have 4/1 - 13/5 but you can’t still subtract that so find the least common denominator of 4/1 and 13/5 which is 5 so now we have 20/5 - 13/5 which equals 7/5 now you have your answer