How to solve this word problem (with statements)

Dear student, Total students = 42 . No. of absent students = 42×2/7 = 12 . Remaining students = 42-12 = 30 . No. of students went for inter school competition = 30×1/5 = 6 . Remaining students = 30-6 = 24 . No. of students went to play on the field = 24×1/8 = 3 . Remaining students left in the class =. 24-3=21 . Regards