14.35.5+10.25.7+20.7 tính nhanh

2 câu trả lời

Đáp án:

14.35.5+10.25.7+20.7=2.7.35.5+250.(4+3)+140=10.35.7+250.4+250.3+140=10.245+1000+750+140=2450+1000+890=2000+400+50+1000+800+50+40=3000+1300+40=4340

Giải thích các bước giải:

14.35.5+10.25.7+20.7=2.7.7.5.5+10.5.5.7+10.2.7=10.7.7.5+10.5.5.7+10.2.7=10.7(7.5+5.5+2)=10.7.62=10.7(60+2)=10.7.60+10.7.2=4200+140=4340