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Câu a bạn chưa giải nhanh, bạn hãy tách nó ra rồi làm theo cách nhanh nhất, những thôi mk k bn trước....còn câu a ai trả lời đc mk sẽ , trả lời câu a thôi cx đc
16/15 x 25/24 x 36/35 x.........x 10000/9999
=16 x 25 x 36......10000 / 15 x 24 x35 .....9999
= ( 4 x 4 ) x ( 5 x 5 ) x ( 6 x 6 ).........( 100 x 100 ) / ( 3 x 5 ) x ( 4 x 6 ) x ( 5 x 7 ) ........( 99 x 101 )
= ( 4 x 5 x 6 x..........100 ) x ( 4 x 5 x 6 ........... x100) / ( 3 x 4 x 5 x 99 ) x ( 5 x 6 x 7.........x 101 )
= 100 x 4 / 3 x 101
= 400/ 303
Hãy k cho mình nha
Bằng 80000/69993
Mình ko chắc nữa số hơi to ( nếu đúng k cho mình nha ✔
1)
\(\left(a\right)37+397+3997+39997\)
\(=40-3+400-3+4000-3+40000-3\)
\(=\left(40+400+4000+40000\right)-\left(3+3+3+3\right)\)
\(=44440-12=44428\)
\(\left(b\right)298+2998+29998+299998\)
\(=300-2+3000-2+30000-2+300000-2\)
\(=\left(300+3000+30000+300000\right)-\left(2+2+2+2\right)\)
\(=333300-8=333296\)
\(\left(c\right)9+99+999+9999+99999\)
\(=10-1+100-1+1000-1+10000-1+100000-1\)
\(=\left(10+100+1000+10000+100000\right)-\left(1+1+1+1+1\right)\)
\(=111110-5=111105\)
2)
\(\left(a\right)\left(2+4+6+...+2002+2004+2006\right)-\left(1+3+5+...+2001+2003+2005\right)\)
\(=\left(2-1\right)+\left(4-3\right)+\left(6-5\right)+...+\left(2002-2001\right)+\left(2004-2003\right)+\left(2006-2005\right)\)
\(=1+1+1+...+1+1+1\)( 1003 số 1 )
\(=1003\)
\(\left(b\right)88-87+86-85+84-83+...+6-5+4-3+2-1\)
\(=\left(88-87\right)+\left(86-85\right)+\left(84-83\right)+...+\left(6-5\right)+\left(4-3\right)+\left(2-1\right)\)
\(=1+1+1+...+1+1+1\)( 44 số 1 )
\(=44\)
\(\left(c\right)100-98+96-94+92-90+...+12-10+8-6+4-2\)
\(=\left(100-98\right)+\left(96-94\right)+\left(92-90\right)+...+\left(12-10\right)+\left(8-6\right)+\left(4-2\right)\)
\(=2+2+2+...+2+2+2\) ( 25 số 2 )
\(=50\)
3)
\(\left(a\right)360-357+354-351+348-345+...+312-309+306-303+300-297\)
\(=\left(360-357\right)+\left(354-351\right)+\left(348-345\right)+...+\left(312-309\right)+\left(306-303\right)+\)\(\left(300-297\right)\)
\(=3+3+3+3+3+3+3+3+3+3+3=33\)
\(\left(b\right)2006-1-2-3-4-...-47-48-49-50\)
\(=2006-\left(1+2+3+4+...+47+48+49+50\right)\)
\(=2006-\frac{\left(50+1\right)\left[\left(50-1\right)+1\right]}{2}\)
\(=2006-1275=731\)
\(\left(c\right)280-276+272-268+264-260+...+216-212+208-204+200-196\)
\(=\left(280-276\right)+\left(272-268\right)+\left(264-260\right)+...+\left(216-212\right)+\left(208-204\right)+\)\(\left(200-196\right)\)
\(=4+4+4+4+4+4+4+4+4+4+4=44\)
Ta có : 1212/3535=12/35 ; 1212/9999=12/99
Từ đề bài => = 12/15 +12/35 +12/63 +12/99
= 6 x ( 2/15 + 2/35 +2/63+2/99 )
= 6 x ( 2/3x5 + ....+ 2/9x11)
= 6 x ( 1/3 - 1/5 +....+1/9 - 1/11)
= 6 x ( 1/3 - 1/11)
= 6 x 8/33 = 48/33
a. 9999.997 + 9999 + 9999 + 9999
= 9999.(997 + 1 + 1 + 1)
= 9999 . 1000
= 9999000
b. (456 . 11 + 912) . 37 : 13 : 74
= (5016 + 912) . 37 : 13 : 74
= 219336 : 13 : 74
= 16872 : 74
= 228
c. 864 . 48 - 432 . 96 : 864 . 48 . 432
= (864 . 48 - 432 . 96) : (864 . 48 . 432)
= 0 : (864 . 48 . 432)
= 0
a. 9999.997 + 9999 + 9999 + 9999
= 9999.(997 + 1 + 1 + 1)
= 9999 . 1000
= 9999000
b. (456 . 11 + 912) . 37 : 13 : 74
= (5016 + 912) . 37 : 13 : 74
= 219336 : 13 : 74
= 16872 : 74
= 228
c. 864 . 48 - 432 . 96 : 864 . 48 . 432
= (864 . 48 - 432 . 96) : (864 . 48 . 432)
= 0 : (864 . 48 . 432)
= 0