Tính nhanh: (60 + 50 + 40 + 30 + 20 + 10) x 50 x 40 + 50 x 30
10 +20 +30 +40 +50 + 60+ 70 +80 +90 = ?
10+20+30+40+50+60+70+80+90+100=???????????????????????????????????????????
10+20+30+40+50+60+70+80+90+100=
10+20+30+40+50+60+70+80+90+100=?
10+20+30+40+50+60+70+80+90+100=???????????????????
1 + 10 + 20 + 30 +40 + 50 + 60 + 70 + 80 + 90= ?
TÍNH:
40+1230=....... 67478+9076=...............
1230+40=........ 9076+67478=...............
TÍNH NHANH
10+20+30+40+50+60+70+80+90+100
=...................................................
=...................................................
=................................................
Tính nhanh :
10 + 20 + 30 + 40 + .... + 50 + 60 + 70 + 80 + 90 + 100