Tính nhanh
a) 215+[170-(215+170)]
b) (-371)-[(-371+29)-229]
c) (18+39)+(158-39-18)
d) 25+[-37-25+(-63)]
25.(215 + 170) + 170.25 + 215.175.Tính bằng cách thuận tiện nhất
\(=25\cdot555+25\cdot1505=51500\)
25.(215 + 170) + 170.25 + 215.175
= 25. 555 + 25. 1505
= 13875 + 37625
= 51500
Tính bằng cách thuận tiện nhất
a. 36 × 25 × 4
b. 18 × 24 : 9
c. 215 × 86 + 215 × 14
a. 36 × 25 × 4 = 36 × 100 = 3600
b. 18 × 24 : 9 = ( 18 : 9) × 24 = 2 × 24 = 48
c. 215 × 86 + 215 × 14 = 215 × ( 86 + 14) = 215 × 100 = 21500
\(\text{tính hợp lý 172-(36+172) (170+25)-170 275-(208+275) -432-(269-432) -371-[1920+(-317) (321-697)+(-321+597) }\)
172 - ( 36+172)
=172 - 36 -172
= ( 172-172)-36
=-36
( 170+25)-170
= 170 + 25 -170
= ( 170-170)+25
= 25
275 - ( 208+275)
= 275 - 208 - 275
= ( 275 - 275) - 208
=-208
Bạn nào giỏi giải hộ mình bài này với ạ :3
a) (- 20) – ( - 5) b) (- 28) : (- 4) c) (-7). (-5) + (-12) : 3 d) (-129) – 37 – (-29) + (-63) e) (217 – 315) – (117 – 215) |
f) (26 - 17) : (-3) + (35 – 11): 2 g) (-5). (11 – 18) – 3. (25 – 11) h) (-15). (-129) + (-15). 29 i) 13. (-125) – 13. (-25) k) 37. (- 135) + (-37). (-35) |
Mình cảm ơn ạ <333
a. -20+5=-15
b. 7
c. 35 + (-4)= 31
d. -129-37+29-63= -100-100 = -200
e. 217 -315-117+215 =100-100=0
f. 15:(-3)+24:2 = -5 + 12 = 7
g. (-5).(-7)-3.(14)= 35 - 42 = -7
H. (-15)x(-129+29) = -15 x -100 =1500
i. 13 x (-125+25) =13 x -100 = -1300
k. 37(-135+35) = 37 x -100 = -3700
Tính nhanh :
a/ 320 x 63 - 16 x 20 + 32 x 370
b/ 35 x 61 + 215 x 5 + 35 x 39 + 57 x 25
c/ 34 x 24 - 94 x 6 + 83 x 48 - 47 x 88
a) 320 x 63 - 16 x 20 + 32 x 370
= 320 x 63 - 320 x + 320 x 37
= 320 x ( 63 - 1 + 37 )
= 320 x 99
= 320 x ( 100 - 1 )
= 320 x 100 - 320
= 32000 - 320 = 31 680
b) 35 x 61 + 215 x 5 + 35 x 39 + 57 x 25
= 5 x 427 + 5 x 215 + 5 x 273 + 5 x 285
= 5 x ( 427 + 215 + 273 + 285 )
= 5 x 1200 = 6000
c) 34 x 24 - 94 x 6 + 83 x 48 - 47 x 88
= 204 x 4 - 4 x 141 + 996 x 4 - 1034 x 4
= 4 x ( 204 - 141 + 996 - 1034 )
= 4 x 25 = 100
4)tìm x:
a) 25 - ( 25 - x ) = 12 + ( 42 - 65 )
b) 215 + (-38) - 54 + 90 - ( -48 + x )=0
c) 15 - ( 15 + x ) = 21
d) 39 + ( x - 39 ) = 50
e) 13 - ( 25 - x)=7
g) x - 15 = -21
i) 12 - (30-x)= -23
k) 31 - ( 17+x) = 18
m) |x| - 5 = 12
a) \(25-\left(25-x\right)=12+\left(42-65\right)\)
\(25-\left(25-x\right)=12+\left(-23\right)\)
\(25-\left(25-x\right)=-11\)
\(25-x=25-\left(-11\right)\)
\(25-x=36\)
\(x=25-36\)
\(x=-11\)
Làm 2 câu dài cho bạn nhá! Mấy câu ngắn tương tự!
a, \(25-\left(25-x\right)=12+\left(42-65\right)\)
\(\Rightarrow25-25+x=12+42-65\)
\(\Rightarrow x=-11\)
b, \(215+\left(-38\right)-54+90-\left(-48+x\right)=0\)
\(\Rightarrow215-38-54+90+48-x=0\)
\(\Rightarrow x=261\)
m, \(\left|x\right|-5=12\)
\(\Rightarrow\left|x\right|=17\Rightarrow\left\{{}\begin{matrix}x=-17\\x=17\end{matrix}\right.\)
Chúc bạn học tốt!!!
a,(18+29)+(158-18-29)
b,(-13-135+49)-(13+49)
c,(-25)+15
d,(-99)+(-100)+(-101)+(-102)
e,34+(-11)+(-4)
f,134+45+(-14)+(-5)
g,21+(-50)+(-1)
h,44+(-213)+|-156|
i,212+[37+(-312)+(-17)]
Tính nhanh
A) 37 x 46 + 37 x 51 + 111
B) 35 x 215 - 35 x 210 - 175
E) 76 x 102 - 76 x 2
C) 85 x 94 + 85 x 2 + 170 x 2
48 x 56 + 28 x 104
G) 206 x 12 - 206 - 206
`@` `\text {Ans}`
`\downarrow`
`A)`
`37 \times 46+37 \times 51+111`
`= 37 \times (46+51)+111`
`= 37 \times 97+111`
`= 3589 +111`
`= 3700`
`B)`
`35 \times 215-35 \times 210-175`
`= 35 \times (215-210)-175`
`= 35 \times 5-175`
`= 175-175=0`
`E)`
`76 \times 102-76 \times 2`
`= 76 \times (102-2)`
`= 76 \times 100`
`= 7600`
`C)`
`85 \times 94+85 \times 2 +170 \times 2`
`= 85 \times (94+2) + 170 \times 2`
`= 85 \times 96+170 \times 2`
`= 8160+340`
`= 8500`
`48 \times 56+28 \times 104`
`= 48 \times 28 \times 2+28 \times 104`
`= 28 \times (48 \times 2+104)`
`= 28 \times (96+104)`
`= 28 \times 200`
`= 5600`
`G)`
`206 \times 12-206-206`
`= 206 \times (12-1-1)`
`= 206 \times 10`
`= 2060`
a) 37 x 46 + 37 x 51 + 111
= 37 x ( 46 + 51 ) + 111
= 37 x 97 + 111
= 3589 + 111
= 3700
b) 35 x 215 - 35 x 210 - 175
= 35 x ( 215 - 210 ) - 175
= 35 x 5 - 175
= 175 - 175
= 0
e) 76 x 102 - 76 x 2
= 76 x ( 102 - 2 )
= 76 x 100
= 7600
c) 85 x 94 + 95 x 2 + 170 x 2
= 7990 + 2 x ( 95 + 170 )
= 7990 + 2 x 265
= 7990 + 530
= 8520
48 x 56 + 28 x 104
= 2688 + 2912
= 5600
g) 206 x 12 - 206 - 206
= 2472 - 206 - 206
= 2266 - 206
= 2060