Tính hợp lý
–( –2019 + 2020 ) + (– 2019 ) – ( 1234 – 2020 )
– 25.800 .( – 0,04).1,25.2020
( 5678 – 975 ) – (– 975 + 678 ) + 4000
– 78. (–245 ) + 245. 22
765.( – 36) – 765. 64
5632.121 + 5632 – 5632.22
Những câu hỏi liên quan
Bài 2: Bỏ ngoặc rồi tính
1/ -2020 + (1543 + 2020)
2/ (245 – 97) – 245
3/ (-145) – (118 – 145)
4/ (-36 + 89) - (145 + 89 – 36)
1/ -2020 + (1543 + 2020)
\(=-2020+1543+2020\)
\(=-2020+2020+1543\)
\(=0+1543\)
\(=1543\)
2/ (245 – 97) – 245
\(=245-97-245\)
\(=245-245-97\)
\(=0-97\)
\(=-97\)
3/ (-145) – (118 – 145)
\(=-145-118+145\)
\(=-145+145-118\)
\(=0-118\)
\(=-118\)
4/ (-36 + 89) - (145 + 89 – 36)
\(=-36+89-145-89+36\)
\(=\left(-36+36\right)+\left(89-89\right)-145\)
\(=0+0-145\)
\(=-145\)
học tốt
1/ -2020+(1543+2020)
=-2020+1543+2020
=(-2020+2020)+1543
=0+1543=1543
2/ (245-97)-245
=245-97-245
=(245-245)-97
=0-97=-97
3/ -145-118+145
=(-145+145)-118
=0-118=-118
4/ -36+89-145-89+36
=(-36+36)+(89-89)-145
=0+0-145=-145
Tính hợp lý :
(-1)+2+(-3)+4+...+(-2019)+2020
(-1) + 2 + (-3) + 4 + ... + (-2019) + 2020
= [ (-1) + 2 ] + [ (-3) + 4 ] + ... + [ (-2019) + 2020 ]
= 1 + 1 + ... + 1
= 1 . 1010
= 1010
(-1)+2+(-3)+4+...+(-2019)+2020
=(-1+2)+(-3+4)+...+(-2019+2020)
=1+1+...+1 (có 1010 số 1)
=1.1010
=1010
\(\left(-1\right)+2+\left(-3\right)+4+...+\left(-2019\right)+2020\)
\(=\left[\left(-1\right)+2\right]+\left[\left(-3\right)+4\right]+...+\left[\left(-2019\right)+2020\right]\)
\(=1+1+...+1\)
\(=1010\)
Xem thêm câu trả lời
tính nhanh:
1234 x 5678 x (630 – 315 x 2): 2020
1234 x 5678 x ( 630 - 315 x 2) : 2020
= 1234 x 5678 x (630 -630 ) : 2020
= 1234 x5678 x 0 : 2020
= 0
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965+452+975+667+245+987=???
nhanh nhất và đúng nhất mk tk nhé!!!
Xem thêm câu trả lời
Bài 1. Tính hợp lý ( nếu có thể): 1) [ (- 2) ^ 2 +7.(-10)]:2+9 2) 2019- lceil157- (357 - 1019) rceil 3) (1173 - 3978) - (173 - 2978) 4) - 113.234 + 129.113 -113.(-105) 5) (2020 - 3257) - (2019 - 3255)
Viết lại hộ mik cái
Ko nhìn đc bn ui!@##
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Viết là bài này ko cần giải đó, hihi!
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Thực hiện phép tính
a, −2020+(2019−1968)−(2019−2020)
b, −37∙16+36∙(−37)−2∙(−37)
c, 1000÷(−10)2+3∙(−5)−(−155)0
a)-2020+(2019-1968)-(2019-2020)=2020+51-(-1)=2071+1=2072
b)-37x16+36x(-37)-2x(-37)=-37x(16+36-2)=-37x50=-1850
c)1000:(-10)2+3.(-5)-(-155).0=-100.2+(-15)-0=-200+-15=-215
28 tháng 6 2021 lúc 15:55
So sánh A và B
A = \(\left(2020^{2019}+2019^{2019}\right)^{2020}\)
B = \(\left(2020^{2020}+2019^{2020}\right)^{2019}\)
Ta có: \(A=\left(2020^{2019}+2019^{2019}\right)^{2020}\)
\(=\left(2019^{2019}+2020^{2019}\right)^{2019}\cdot\left(2019^{2019}+2020^{2019}\right)\)
\(\Leftrightarrow\dfrac{A}{B}=\dfrac{\left(2019^{2019}+2020^{2019}\right)^{2019}\cdot\left(2019^{2019}+2020^{2019}\right)}{\left(2020^{2020}+2019^{2020}\right)^{2019}}\)
\(\Leftrightarrow\dfrac{A}{B}=\dfrac{2019^{2019}+2020^{2019}}{2019+2020}>1\)
\(\Leftrightarrow A>B\)
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\(\dfrac{2020^{2018}-1}{2020^{2019}+2019}\)với B=\(\dfrac{2020^{2019}+1}{2020^{2020}+2019}\)
\(A=\dfrac{2020^{2018}-1}{2020^{2019}+2019}\)
\(B=\dfrac{2020^{2019}+1}{2020^{2020}+2019}\)
Ta có :
\(A-B=\dfrac{2020^{2018}-1}{2020^{2019}+2019}-\dfrac{2020^{2019}+1}{2020^{2020}+2019}\)
\(\Rightarrow A-B=\dfrac{\left(2020^{2018}-1\right)\left(2020^{2020}+2019\right)-\left(2020^{2019}+2019\right)\left(2020^{2019}+1\right)}{\left(2020^{2019}+2019\right)\left(2020^{2020}+2019\right)}\)
\(\Rightarrow A-B=\dfrac{2020^{4038}+2019.2020^{2018}-2020^{2020}-2019-2020^{4038}-2020^{2019}-2019.2020^{2018}-2029}{\left(2020^{2019}+2019\right)\left(2020^{2020}+2019\right)}\)
\(\Rightarrow A-B=\dfrac{-\left(2020^{2020}+2020^{2019}+2.2019\right)}{\left(2020^{2019}+2019\right)\left(2020^{2020}+2019\right)}\)
mà \(\left\{{}\begin{matrix}-\left(2020^{2020}+2020^{2019}+2.2019\right)< 0\\\left(2020^{2019}+2019\right)\left(2020^{2020}+2019\right)>0\end{matrix}\right.\)
\(\Rightarrow A-B< 0\)
\(\Rightarrow A< B\)
Vậy ta được \(A< B\)
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tính nhanh :
a) 946 . 3 + 496 . 4 - 496 . 6
b) 2019 . (2020 + 1) - 2019 . 2020
c) 436 + 324 . (234 - 1) - 234 . 324 + 324
d) 472 . (36 - 1) + 35 . 8
Trả lời
a)964.3+496.4-496.6
=964.3+[496.(4-6)]
=964.3+(-992)
=2892+(-992)
=1900
b)2019.(2020+1)-2019.2020
=2019.2020.2019-2019.2020
=2019
c)436+324.(234-1)-234.324+324
=436+324.234-324-234.324+324
=436
d)472.(36-1)+35.8
=472.35+35.8
=35.(472+8)
=35.480
=16 800
Ko chắc nha, sai thì cho mk xl vì làm phiền bạn !
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b)2019.(2020+1)-2019.2020
=2019.(2020+1-2020)
=2019.1
=2019
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