50+30=80 78-2-7=69 1x4=4 50-50=0 91-3-1=87 2x4=8 20+80=100 72-4-2=66 4x8=32 70+40=110 97-2-1=94 6x3=18 50+90=140 82-13-2=67 9x9=81 10+80=90 63-15-1=47 4x5=20 30+40=70 70-22-8=40 3x9=27 50-20=30 99-1-0=98 7x5=35 14+39=53 407+231=638 90x69=6210