18×7=10×7+8×7=70+56=126
17×8=10×8+7×8=80+56=136
19×6=10×6+9×6=90+54=144
106×7-107×6=(100×7+6×7)-(100×6+7×6)=(700+42)-(600+42)=742-642=100
203×4-204×3=(800+12)-(600+12)=812-612=200
150×6-160×5=(600+300)-(500+300)=900-800=100
180-120×5÷6=180-(120÷6)×5=180-20×5=180-100=80
210-140×5÷7=210-(140÷7)×5=210-20×5=210-100=110
240-160×5÷8=240-20×5=240-100=140