Bài 2 : Tính bằng cách thuận tiện nhất
a) \(\frac{4^{17}x3^4x9^6}{6^{13}}\)
b) \(\frac{2^{16}+2^8}{2^{13}+2^5}\)
Tính bằng cách thuận tiện nhất :
a) \(\frac{2}{5}+\frac{1}{6}+\frac{3}{5}\)
b) \(\frac{9}{13}+\frac{4}{13}+\frac{2}{3}\)
\(a,\frac{2}{5}+\frac{1}{6}+\frac{3}{5}\)
\(=\left(\frac{2}{5}+\frac{3}{5}\right)+\frac{1}{6}\)
\(=1+\frac{1}{6}\)
\(=\frac{7}{6}\)
Hok tốt!~
\(\frac{2}{5}+\frac{1}{6}+\frac{3}{5}\)
\(=\frac{2}{5}+\frac{3}{5}+\frac{1}{6}\)
\(=\frac{5}{5}+\frac{1}{6}\)
\(=1+\frac{1}{6}\)
\(=1\frac{1}{6}=\frac{7}{6}\)
tính bằng cách thuận tiện nhất :
a) 17 / 23 + ( 1 - 17 / 23 )
b) 17 / 12 + 9 / 7 - ( 2 / 7 + 5 / 12 )
c) 7 / 13 - ( 4 / 7 - 6 / 13 )
d) 7 / 18 + 3 / 16 + 11 / 18 + 13 / 16
a) 17/23+(1-17/23)
=17/23+1-17/23
=1
b)17/12+9/7-(2/7+5/12)
=17/12+9/7-2/7-5/12
=1+1
=2
c)
7/13-(4/7-6/13)
=7/13-4/7+6/13
=1-4/7
=3/7
a,17/23 + (1 - 17/23)
= 17/23 + 6/23
= 23/23 = 1
b,17/12 + 9/7 - (2/7 + 5 /12)
= (17/12 - 5/12) + (9/7 + 2/7)
= 1+1 = 2
c, 7/13 - ( 4/7 -6/13 )
= 7/13 - 4/7+ 6/13
= (7/13 + 6/13) -4/7
= 13/13 -4/7
= 1 -4/7 = 3/7
hok tốt✍️ ✍️
tính bằng cách thuận tiện nhất :
a) 17 / 23 + ( 1 - 17 / 23 )
b) 17 / 12 + 9 / 7 - ( 2 / 7 + 5 / 12 )
c) 7 / 13 - ( 4 / 7 - 6 / 13 )
d) 7 / 18 + 3 / 16 + 11 / 18 + 13 / 16
tính bằng cách thuận tiện nhất :
a) 17 / 23 + ( 1 - 17 / 23 )
b) 17 / 12 + 9 / 7 - ( 2 / 7 + 5 / 12 )
c) 7 / 13 - ( 4 / 7 - 6 / 13 )
d) 7 / 18 + 3 / 16 + 11 / 18 + 13 / 16
a) 17/23 + (1 - 17/23)
= 17/23 + 1 - 17/23
= (17/23 - 17/23) + 1
= 0 + 1 = 1
b) 17/12 + 9/7 - (2/7 + 5/12)
= 17/12 + 9/7 - 2/7 - 5/12
= (17/12 - 5/12) + (9/7 - 2/7)
= 1 + 1 = 2
c) 7/13 - (4/7 - 6/13)
= 7/13 - 4/7 + 6/13
= (6/13 + 6/12) - 4/7
= 1 - 4/7 = 3/7
d) 7/18 + 3/16 + 11/18 + 13/16
= (7/18 + 11/18) + (3/16 + 13/16)
= 1 + 1 = 1
d) sửa 7/18 + 3/16 + 11/18 + 13/16
= (7/18 + 11/18) + (3/16 + 13/16)
= 1 + 1
= 2
Tính bằng cách thuận tiện nhất:
a) 16, 2 x 3, 7 + 5, 7 x 16, 2 - 7, 8 x 4, 8 - 4, 6 x 7, 8 : 11, 2 + 12, 3 + 13, 4 - 12, 6 - 11, 5 - 10, 4
tính bằng cách thuận tiện nhất
a,17/13-14/23+9/13-9/23
b,49/5-1/2-1/4-1/8-1/16-1/32
a. \(\dfrac{17}{13}-\dfrac{14}{23}+\dfrac{9}{13}-\dfrac{9}{23}=\left(\dfrac{17}{13}+\dfrac{9}{13}\right)-\left(\dfrac{14}{23}+\dfrac{9}{23}\right)=\dfrac{26}{13}-\dfrac{23}{23}=2-1=1\)
b.\(\dfrac{49}{5}-\dfrac{1}{2}-\dfrac{1}{4}-\dfrac{1}{32}-\dfrac{1}{16}-\dfrac{1}{32}=\dfrac{49}{5}-\left(1-\dfrac{1}{32}\right)=\dfrac{44}{5}+\dfrac{1}{32}=\dfrac{1413}{160}\)
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20= ?
Tính bằng cách thuận tiện nhất nha.
AI NHANH MK TÍCH
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20
=(1+19)+(2+18)+(3+17)+(4+16)+(5+15)+(6+14)+(7+13)+(8+12)+(9+11)+20+10
=20+20+20+20+20+20+20+20+20+20+10
=20×10+10
=200+10
=210
= ( 1 + 19 ) + ( 2 + 18 ) + ( 3 + 17 ) + (4 + 16 ) + ( 5 + 15 ) + ( 6 + 14 ) + ( 7 + 13 ) + ( 8 + 12) + ( 9+ 11 ) + 20
= 20 + 20 + 20 +20 + 20 +20 + 20 + 20 + 20 +20
= 20 x 10
= 200
tui đầu tiên đó
Ta có : \(1+2+3+...+19+20\)
\(=\frac{\left(20+1\right).20}{2}=\frac{21.20}{2}=210\)
Tính bằng cách thuận tiện nhất :
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20=?
ai đầu tiên mik tick cho hi hi
(19+1)+(18+2)+(17+3)+(16+4)+(15+5)+(14+6)+(13+7)+(12+8)+(11+9)+20)+10
=20+20+20+20+20+20+20+20+20+20=(20*10)+10
=210
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20
=(1+19)+(2+18)+(3+17)+(4+16)+(5+15)+(6+14)+(7+13)+(8+12)+(9+11)+(10+20)
=20+20+20+20+20+20+20+20+20+30
=(20 x 9) + 30
=180 + 30
=210
tk nha
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20
= (1+19)+(2+18)+(3+17)+(4+16)+(5+15)+(6+14)+(7+13)+(8+12)+(9+11)+20+10
= 20 + 20 + 20 + 20 + 20 + 20 + 20 + 20 + 20 + 20 + 10
= 10 . 10 +10
= 100 + 10 = 110
Tính bằng cách thuận tiện nhất
A. 2/5*4/7+3/5*4/7
B. 17/13*12/17-4/13*12/17
C. 9/14 : 6/7+5/14 : 6/7
D. 9/12 : 7/9*12/19
A =\(\frac{2}{5}\times\frac{4}{7}+\frac{3}{5}\times\frac{4}{7}\) B = \(\frac{17}{13}\times\frac{12}{17}-\frac{4}{13}\times\frac{12}{17}\) C = \(\frac{9}{14}:\frac{6}{7}+\frac{5}{14}:\frac{6}{7}\) D =\(\frac{9}{12}:\frac{7}{9}\times\frac{12}{19}\)
= \(\frac{4}{7}\times\left(\frac{2}{5}+\frac{3}{5}\right)\) =\(\left(\frac{17}{13}-\frac{4}{13}\right)\times\frac{12}{17}\) = \((\frac{9}{14}+\frac{5}{14}):\frac{6}{7}\) = \(\frac{9}{12}\times\frac{9}{7}\times\frac{12}{19}\)
=\(\frac{4}{7}\times1\) = \(1\times\frac{12}{17}\) = \(1:\frac{6}{7}\) = \(\frac{9\times9\times12}{12\times7\times19}\)
=\(\frac{4}{7}\) = \(\frac{12}{17}\) =\(\frac{7}{6}\) = \(\frac{9\times9}{7\times19}=\frac{81}{133}\)