请运用所学知识,谈谈“总理语录”涉及哪些知识?
78-50-9=____,72-2-30=____
35+6+40=____,47+9-20=____
17+3+15=____,75-50+14=____
49-9-30=____,28+20+2=____
99-20+6=____,100-30-7=____
16+15-7=____,70-30+33=____
85-6-19=____,6+24+30=____
75-20-30=____,62-5+7=____