1/10+1/15+1/16+...+1/60
1/10+1/15+1/16+...+1/60
3.<,>,=
3-5/6.......1+5/6 41/60-11/60........3/8+1/8
2/5+4/15.......9/10-3/5 1/3-1/12......7/8-5/16
3.<,>,=
3-5/6....>...1+5/6 41/60-11/60....=....3/8+1/8
2/5+4/15....>...9/10-3/5 1/3-1/12..<....7/8-5/16
3-5/6 > 1+5/6
41/60 -11/60 = 3/8+1/8
2/5+4/15 > 9/10-3/5
1/3-1/12 < 7/8-5/16
1/5+4/10+9/15+16/20+25/25+36/30+49/35+64/60+81/45
Tính nhanh:
a,1/4+2/5+6/8+9/15+8/1
b,1/2+2/4+3/6+4/8+5/10+6/12+7/14+8/16+9/18+10/20
c,1/10+4/20+9/30+16/40+25/50+36/60+49/70+64/80+81/90
a; \(\dfrac{1}{4}\) + \(\dfrac{2}{5}\) + \(\dfrac{6}{8}\) + \(\dfrac{9}{15}\) + \(\dfrac{8}{1}\)
= (\(\dfrac{1}{4}\) + \(\dfrac{6}{8}\)) + (\(\dfrac{2}{5}\) + \(\dfrac{9}{15}\)) + \(\dfrac{8}{1}\)
= (\(\dfrac{1}{4}\) + \(\dfrac{3}{4}\)) + (\(\dfrac{2}{5}\) + \(\dfrac{3}{5}\)) + 8
= 1 + 1 + 8
= 2 + 8
= 10
b; \(\dfrac{1}{2}\) + \(\dfrac{2}{4}\) + \(\dfrac{3}{6}\) + \(\dfrac{4}{8}\) + \(\dfrac{5}{10}\) + \(\dfrac{6}{12}\) + \(\dfrac{7}{14}\) + \(\dfrac{8}{16}\) + \(\dfrac{10}{20}\)
= \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) x (\(\dfrac{2}{2}\) + \(\dfrac{3}{3}\) + \(\dfrac{4}{4}\) + \(\dfrac{5}{5}\)+ \(\dfrac{6}{6}+\dfrac{7}{7}+\dfrac{8}{8}\) + \(\dfrac{10}{10}\))
= \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) x (1 + 1 +1 + 1+ 1+ 1+ 1 +1)
= \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) x 1 x 8
= \(\dfrac{1}{2}\) + \(\)\(\dfrac{1}{2}\) x 8
= \(\dfrac{1}{2}\) + 4
= \(\dfrac{9}{2}\)
c; \(\dfrac{1}{10}\) + \(\dfrac{4}{20}\) + \(\dfrac{9}{30}\)+\(\dfrac{16}{40}+\dfrac{25}{50}+\dfrac{36}{60}+\dfrac{49}{70}+\dfrac{64}{80}+\dfrac{81}{90}\)
= \(\dfrac{1}{10}+\dfrac{2}{10}+\dfrac{3}{10}+\dfrac{4}{10}+\dfrac{5}{10}+\dfrac{6}{10}+\dfrac{7}{10}+\dfrac{8}{10}+\dfrac{9}{10}\)
= \(\dfrac{1+2+3+4+5+6+7+8+9}{10}\)
= \(\dfrac{\left(1+9\right)+\left(2+8\right)+\left(3+7\right)+\left(4+6\right)+5}{10}\)
= \(\dfrac{10+10+10+10+5}{10}\)
= \(\dfrac{\left(10+10+10+10\right)+5}{10}\)
= \(\dfrac{10\times4+5}{10}\)
= \(\dfrac{45}{10}\)
= \(\dfrac{9}{2}\)
Tính nhanh:
a,1/4+2/5+6/8+9/15+8/1
b,1/2+2/4+3/6+4/8+5/10+6/12+7/14+8/16+9/18+10/20
c,1/10+4/20+9/30+16/40+25/50+36/60+49/70+64/80+81/90
a; \(\dfrac{1}{4}\) + \(\dfrac{2}{5}\) + \(\dfrac{6}{8}\) + \(\dfrac{9}{15}\) + \(\dfrac{8}{1}\)
= (\(\dfrac{1}{4}\) + \(\dfrac{6}{8}\)) + (\(\dfrac{2}{5}\) + \(\dfrac{9}{15}\)) + 8
= (\(\dfrac{1}{4}\) + \(\dfrac{3}{4}\)) + (\(\dfrac{2}{5}\) + \(\dfrac{3}{5}\)) + 8
= 1 + 1 + 8
= 2 + 8
= 10
b; \(\dfrac{1}{2}\) + \(\dfrac{2}{4}\) + \(\dfrac{3}{6}\) + \(\dfrac{4}{8}\) + \(\dfrac{5}{10}\) + \(\dfrac{6}{12}\) + \(\dfrac{7}{14}\) + \(\dfrac{8}{16}\) + \(\dfrac{9}{18}\) + \(\dfrac{10}{20}\)
= \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\)
= \(\dfrac{1}{2}\) x 10
= 5
c; \(\dfrac{1}{10}\) + \(\dfrac{4}{20}\) + \(\dfrac{9}{30}\)+\(\dfrac{16}{40}+\dfrac{25}{50}+\dfrac{36}{60}+\dfrac{49}{70}+\dfrac{64}{80}+\dfrac{81}{90}\)
= \(\dfrac{1}{10}+\dfrac{2}{10}+\dfrac{3}{10}+\dfrac{4}{10}+\dfrac{5}{10}+\dfrac{6}{10}+\dfrac{7}{10}+\dfrac{8}{10}+\dfrac{9}{10}\)
= \(\dfrac{1+2+3+4+5+6+7+8+9}{10}\)
= \(\dfrac{\left(1+9\right)+\left(2+8\right)+\left(3+7\right)+\left(4+6\right)+5}{10}\)
= \(\dfrac{10+10+10+10+5}{10}\)
= \(\dfrac{\left(10+10+10+10\right)+5}{10}\)
= \(\dfrac{10\times4+5}{10}\)
= \(\dfrac{45}{10}\)
= \(\dfrac{9}{2}\)
Bài 1: tìm ƯCLN của
24; 36 và 60
12; 15 và 10
24;16 và 8
9 và 81
11 và 15
1 và 10
150 và 84
46 và 138
16; 32 và 112
14; 82 và 124
15; 55 và 75
150; 84 và 30
24; 36 và 160
24 = 23.3; 36 = 24.34; 60 = 22.3.5
ƯCLN( 24; 36; 60) = 22.3 = 12
12 = 22.3; 15 = 3.5; 10 = 2.5
ƯCLN(12; 15; 10) = 1
24 = 23.3; 16 = 24; 8 = 23
ƯCLN(24; 16; 8) = 23
9 = 32; 81 = 34
ƯCLN( 9; 81) = 9
11 = 11; 15 = 3.5
ƯCLN( 11; 15) = 1
1 = 1; 10 = 2.5
ƯCLN(1; 10) = 1
150 = 2.3.52; 84 = 22.3.7
ƯCLN( 150; 84) = 6
46 = 2.23; 138 = 2.3.23
ƯCLN(46; 138) = 2.23 = 46
16 = 24; 32 = 25; 124 = 22.31
ƯCLN( 16; 32; 124) = 22 = 4
14 = 2.7; 82 = 2.41; 124 = 22.31
ƯCLN( 14; 82; 124) = 2
so sánh
a, A=\(\frac{10^{17}-1}{10^{16}-1}vaB=\frac{10^{16}+2}{10^{15}+2}\)
b,\(C=\frac{2017^{15}+1}{2017^{16}+1}vaO=\frac{2017^{16}-1}{2017^{17}-1}\)
c,\(E=\frac{99^{15}-1}{99^{16}-1}vaF=\frac{99^{16}+2}{99^{17}+2}\)
Tính bằng cách hợp lý:
a) (44*52*60) : (11*13*15)
b) (16*17-5) : (16*16+11)
c) (27*700-24*45*20) : (45-40+35-30+25-20+15-10+5)
d) 1+6+11+16+...+46+51
a) (44 x 52 x 60) : (11 x 13 x 15)
= (44 : 11) x ( 52 : 13) x (60 : 15)
= 4 x 4 x 4 = 64
d) 1 + 6 + 11 + 16 + ... + 46 + 51
Ta có : 1 + 6 + 11 + 16 + ... + 46 + 51 ( có 11 số )
= (51 + 1) x 11 : 2 = 286
a, Ta thấy 44:11=4 , 52;13=4 , 60:15=4, => 4*4*4=64
b,Ta có : 16*17-5=16*(16+1)-5=16*16+16-5=16*16+11 Ta thấy Cụm 1 = Cụm 2 => Đáp án =1
so sánh A=10^15+1/10^16+1
B=10^16+1/10^17+1
TRƯỚC TIÊN TA SO SÁNH 10 VỚI 10B
10A=10^16+10/10^16+1=1\(\frac{9}{16+1}\)
10B=10^17+10/10+17+1=1\(\frac{9}{17+1}\)
VÌ 9/16+1>9/17+1
=>10A>10B
=>A>B
AI TÍCH MK ;MK TÍCH LẠI