tinh nhanh :2003*2777-2777*2003
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368*2003-66*2003-2*2003
= 2003 * ( 368 - 66 - 2 )
= 2003 * 300
= 600900
tinh nhanh 368*2003-66*2003-2*2003
=2003.(368-66-2)
=2.300=600900
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Tinh nhanh
2003×14+1998+2001×2002 / 2002+2002×503+504×2003
Viet ro loi giai nhe! Ai nhanh mk tk cho!
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2003x14+1998+2001x2002/2002+2002x503+504x2003 =2003x14+1998+2001x1+2002x503+504x2003 =2003x14+1998+2001+2002x503+504x2003 =28042+1998+2001+1007006+1009512 =(28042+1009512+1007006)+1998+2001 =2044560+1998+2001=2048559 TK MIk nha bn! mk tra loi dau tien ma ! Giu loi hua nhe!
2003 x 14 + 1988 + 2001 x 2002
=28042 + 1988 + 4006002
=4036032
2002 + 2002 x 503 +504 x 2002
=2002 x 1 + 2002 x 503 + 504 x 2002
=2002 x (1 + 503 + 504)
=2002 x 908
=1817816
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bài2 :
Ta có x1 + x2 + x3 + x4 +....+x49 + x50 + x51 = 0
=> (x1 + x2) + (x3 + x4)+....+(x49+ x50) + x51 = 0
=> [1 + 1 + 1+.....+ 1] +x51 = 0
Ta có từ x1 ---> x50 có 50 số => trong [..] có 25 số 1
=> 25 + x51 =0 => x51 = -25
Có x50+ x51 = 1 => x50= 1- x51 = 26
bài 1:
a)=(-2003)+(-21)+75+2003
=[(-2003)+2003]+(-21)+75
=0+(-21)+75
=(75-21)
=54
b)=1152-374-1152+(-65)+374
=[(1152-1152)]+[(-374)+374]+(-65)
=0+0+(-65)
=-65
bài 2 tự làm nhé mình đi ăn cơm đã
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\(\frac{2003}{1\cdot2}+\frac{2003}{2\cdot3}+...+\frac{2003}{2002\cdot2003}\)
\(=2003\cdot\left(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+...+\frac{1}{2002\cdot2003}\right)\)
\(=2003\cdot\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\cdot\cdot\cdot+\frac{1}{2002}-\frac{1}{2003}\right)\)
\(=2003\cdot\left(1-\frac{1}{2003}\right)\)
\(=2003\cdot\frac{2002}{2003}\)
\(=\frac{2003\cdot2002}{2003}\)
\(=2002\)
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\(\left(7^{2003}+7^{2002}\right):7^{2001}\)
\(=\left(7^{2003}+7^{2002}\right).\frac{1}{7^{2001}}\)
\(=\frac{7^{2003}}{7^{2001}}+\frac{7^{2002}}{7^{2001}}\)
\(=7^2+7=49+7=56\)
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2002 x 8648 + 2002 x 1352 + (1352-352)
=2002 x (8648+1352) + 1000
= 2002 x 10000 +1000
=20020000+1000
=20021000
Nha bạn
2002 x 8648 + 2003 x 1352 - 352
= 2002 x 8648 + ( 2002 + 1 ) x 1352 - 352
= 2002 x 8648 + 2002 x 1352 + 1352 - 352
= 2002 x ( 8648 + 1352 ) + 1000
= 2002 x 10000 + 1000
= 20020000 + 1000
= 20021000
\(2003\times2777-2777\times2003\)
\(=2003\times\left(2777-2777\right)\)
\(=0\)
p/s: chúc bạn học tốt
\(2003\cdot2777-2777\cdot2003\)
\(=2777\cdot\left(2003-2003\right)\)
\(=2777\cdot0\)
\(=0\)