Tính nhanh
(413-127+42)-(413+127-48)
Tính nhanh:
a) A= 413(413-26)+169
A=\(413^2-413.26+13^2=413^2-2.413.13+13^2\)
=> A=\(\left(413-13\right)^2=400^2=160000\)
chuc ban hoc tot
Tính (-48)+127+(-52)+73 (-38)x45+(-38)x55 (-125)+371+(-875)+629+150 271+(-392)+729+(-608+(-123) (-48)x25+25x(-52) 47x(-11)+47 56-7x8+11 -42+51+2+(-11)+40
a) \(\left(-48\right)+127+\left(-52\right)+73\)
\(=\left(-48-52\right)+\left(127+73\right)\)
\(=-100+200\)
\(=100\)
b) \(\left(-38\right)\cdot45+\left(-38\right)\cdot55\)
\(=\left(-38\right)\cdot\left(45+55\right)\)
\(=\left(-38\right)\cdot100\)
\(=-3800\)
c) \(\left(-125\right)+371+\left(-875\right)+629+150\)
\(=\left(-125-875\right)+\left(371+629\right)+150\)
\(=-1000+1000+150\)
\(=150\)
d) \(271+\left(-392\right)+729+\left(-608\right)+\left(-123\right)\)
\(=\left(271+729\right)+\left(-392-608\right)-123\)
\(=1000-1000-123\)
\(=-123\)
e) \(\left(-48\right)\cdot25+25\cdot\left(-52\right)\)
\(=25\cdot\left(-48-52\right)\)
\(=25\cdot-100\)
\(=-2500\)
f) \(47\cdot\left(-11\right)+47\)
\(=47\cdot\left(-11+1\right)\)
\(=47\cdot-10\)
\(=-470\)
g) \(56-7\cdot8+11\)
\(=56-56+11\)
\(=0+11\)
\(=11\)
h) \(-42+51+2+\left(-11\right)+40\)
\(=\left(-42+2\right)+\left(51-11\right)+40\)
\(=-40+40+40\)
\(=0+40\)
\(=40\)
a: =-48-52+127+73
=200-100
=100
b; \(=-38\left(45+55\right)=-38\cdot100=-3800\)
c: \(=-125-875+371+629+150\)
=-1000+1000+150
=150
d: =271+729-392-608-123
=1000-1000-123
=-123
e: =25(-48-52)
=25*(-100)
=-2500
f: =47(-11+1)
=47(-10)
=-470
g: =56-56+11
=11
h: =-42+2+51-11+40
=-40+40+40
=40
Tính nhanh: B = − 4 13 + 3 5 + 1 3 − 9 13 + 2 5
B = − 4 13 + 3 5 + 1 3 − 9 13 + 2 5 = − 4 13 + − 9 13 + 3 5 + 2 5 + 1 3 = ( − 1 ) + 1 + 1 3 = 0 + 1 3 = 1 3
tính nhanh: 127*57+44*127-127
127 . 57 + 44 . 127 - 127
= 127 . ( 57 + 44 - 1 )
= 127 . 100
= 12 700
Tính nhanh
A.(13+25)+(24-13-42-25)
B.(215-34+127)-(315-144-227)
A.( 13 + 25 ) + ( 24 - 13 - 42 - 25 )
= 13 + 25 + 24 - 13 - 42 - 25
= ( 13 - 13 ) + ( 25 - 25 ) + ( 24 - 42 )
= 0 + 0 + ( - 18 )
= -18
B. ( 215 - 34 + 127 ) - ( 315 - 144 - 227 )
= 215 - 34 + 127 - 315 + 144 + 227
= ( 215 - 315 ) + ( 144 - 34 ) + ( 127 + 227 )
= - 100 + 110 + 354
= 10 + 354
= 364
tính hợp lí:
a.58+42+32+58+72+42
b.133:7+154:7+413:7:4
a.58+42+32+58+72+42 b.133:7+154:7+413:7:4
=(58+42)+(58+42)+72+32 =133:7+154:7+413:4:7
=100+100+72+32 = 133:7+154:7+103,25 :7
=200+104 = (133+154+103,25):7
=304 = 390,25:7
= 55.75
\(a.58+42+32+58+72+42\)
\(=\left(58+42\right)+\left(58+42\right)+72+42\)
\(=100+100+104\)
\(=304\)
Tính nhanh
( 1+3+5+7+…+2003+2005) x (125 125 x 127 – 127 127 x 125)
( 1+3+5+7+…+2003+2005) x (125 125 x 127 – 127 127 x 125)
= ( 1+3+5+7+…+2003+2005) x (125 x 1001 x 127 – 127 x 1001x 125)
= ( 1+3+5+7+…+2003+2005) x 0 = 0
Tính nhanh
( - 127 ) x 73 + 127 x ( -27 )
(-127) x 73+(-127) x 27
=(-127) . (73+27)
=(-127).100
=-12700
tính nhanh:166.[-127+234]-234.[166+127]
166.(-127+234)-234.(166+127)
= 166.(-127)+166.234-234.166-234.127
=[166.(-127)-234.127]+(166.234-234.166)
=(-127).(166+234)+0
=(-127).400
=-50800
Trl :
166×(-127+234)-234×(166+127)
=166*(-127)+166*234-234*166+234*127
=[166*234-234*166]+[166*(-127)+234*127]
=[166*(234-234)]+[(-166)*127+234*127]
=(166*0)+[127*(-166+234)]
=0+127*68
=127*68
=8636
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