Tính nhanh
-65.(87-17)-87.(17-65)
tính nhanh:
a)-65.(87-17) - 87.(17-65)
b)87.(13-18) - 13.(87+18)
tính nhanh: -65 .(87-17)-87.(17-65)
-65.(87 - 17) - 87.(17 - 65) = 65.(17 - 87) - 87.17 + 87.65 = 65.17 - 65.87 + 65.87 - 87.17 = (65 - 87).17 = -22.17 = -374
tính nhanh : a) 135-35.(-37)+37.(-42-48)
b ) -65.(87-17)-87.(17-65)
a)135-35.(-37)+37.(-42-48)=-4490
b)-65.(87-17)-87.(17-65)=-374
Tính: -65.(87 - 17) - 87.(17 - 65)
− 65 ( 87 − 17 ) − 87 ( 17 − 65 ) = − 65.87 + 65.17 − 87.17 + 87.65 = 87.65 − 65.87 + 17 65 − 87 = 0 + 17. − 22 = − 374.
Tính nhanh
a,-128.(-25+89)+128(89-125)
b, 15.(17-111)-17.(222+15)
c,-65.(87-17)-87.(17-65)
d,-54+38+12.(-54)-50.(-54)
a, - 128 . (-25+89) + 128.(89-125)
= 128 . - (-25 +89) + 128 . (89 - 125)
= 128 . [-(-25+89)+(89 - 125)]
= 128. (25+89+89-125)
= 128 . (89.2+-100)=128.78=(120+8).(70+8)= 8.190=1520
17-65.(87-17)-87.(17-65)
17-65.(87-17)-87.(17-65)
=17-65.87-17.87.17-65
=(17-17).(65-65).(87-87)-17
=0.0.0-17
=0-17
=-17
87-17.(-65)+(-87).(17-65)
-65*(87-17)-87*(17-65)
=-65.87+65.17-87.17+65.87=
=17(65-87)=-17.22
-65 . ( 87 -17 ) -87 . ( 17 - 65 )
-65 . ( 87 -17 ) -87 . ( 17 - 65 )
=(-65).70-87.(-48)
=(-4550)-(-4176)
=(-374)
\(-65.\left(87-17\right)-87.\left(17-65\right)\)
\(=-65.70-87.\left(-48\right)\)
\(=\left(-4550\right)-\left(-4176\right)=-374\)