a) (25 x 3 - 15 x 5) x 99
= (25 x 3 - 5 x 3 x 5) x 99
= (25 x 3 - 25 x 3) x 99
= 0 x 99 = 0
b) 140 + 30 + 60 + 80 + 30 + 170 + 120 + 50
= (140 + 60) + (30 + 170) + (80 + 120) + (60 + 30 + 50)
= 200 + 200 + 200 + 200 + 140
= 200 x 4 + 140 = 800 + 140 = 940
Tính nhanh
A. (25x3-15x5)x99
B. 140+30+60+80+30+170+120+50
tính nhanh ;
10 + 20 + 30 + 40 + 50 + 60 + 70 + 80 + 90 + 100
tk nhé
Tính nhanh :
\(10+20+30+40+50+60+70+80+90\)
(60-50)+(40-30)+(90-80)-20=????
90 + 90 + 10 + 20 + 30 + 40 + 50 + 60 - 120 = ?
10+20+30+40+50+60+70+80+90+100=..................
Tính:
A=1+2+3+4+5+5+6+7+8+9+10
B=10+20+30+40+50+50+60+70+80+90+100
10 + 20 + 30 + 40 + 50 + 60 + 70 + 80 + 90 +100 + 200 + 300 =
TOÁN HACK NÃO
10+10=120
20+20=140
30+30=160
40+40=???
