cmr;M=1/41+1/42+1/43+..+1/80>7/12
CMR 1/41+1/42+1/43+...+1/79+7/80 <7/12
Cmr 1/41+4/42+4/43+.........+1/79+1/80>7/12
tinh 42/20x24+42/24x28+...+42/96x100
CMR 41/2*42/2....80/2=1*3*5...79
Tính nhanh
a) 32.(-64)-64
b)-54 -76 +12.(-76)-76.(-34)
c)19-42.(-19)+38.5
32-42.(-16)+48.5
Bài 2: Tính hợp lí
a) 32.(- 64) – 64.68 b) - 54.76 + 12.(- 76) – 76.(- 36) | c) 8.19 – 42.(- 19) + 38.5 d) 74.(- 41) + 41.24 | e) – 43.38 + 12.(- 43) – 50.(- 43) f) 32 – 42.(- 16) + 48.5 – (- 16) |
tinh
32.(-64) - 64
-54 . 76 + 12 . (-76) - 76 . (-34)
19 - 42 , (-19) + 38 . 5
32 - 42 . (-16) + 48 .5
(-1)^3 . (-2)^3 . (-3)^2
5^3 . [ -7 + (-2)^3] + 4
giup minh nha mai minh nop rui
CMR: \(\frac{1}{41}+\frac{1}{42}+\frac{1}{43}+...+\frac{1}{80}>\frac{ }{ }\)7/12