38+20= thirty-eight, forty eight, fifty eight.
63+40= sixty-three, seventy-three, eighty-three, ninety-three, one-hundred three
42+30=forty-two, fifty-two, sixty-two, seventy-two, eighty-two.77-30= Seventy-seven sixty-seven, fifty-seven, forty-seven 53-40=fifty-three, forty-three, thirty-three, twenty-three, thirteen
91-20= Ninety-one, eighty-one, seventy-one
This method is where you count up and down by tens.