Tính S = 7+7/3+7/6+7/10+7/15+7/21+7/28+7/36+7/45+7/55
Những câu hỏi liên quan
2-5/3+7/6-9/10+11/15-13/21+15/28-17/36+19/45-21/55+23/66
8 tháng 8 2015 lúc 10:32
Tính nhanh: A=4/3+7/6+11/10+16/15+22/21+29/28+37/36+46/45
A=4/3+7/6+11/10+16/15+22/21+29/28+37/36+46/45
A = ( 1 + 1/3 ) + ( 1 + 1/6 ) + ( 1 + 1/10 ) + ( 1 + 1/15 ) + ( 1 + 1/21 ) + ( 1 + 1/28 ) + ( 1 + 1/36 ) + ( 1 + 1/45 )
A = ( 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 ) + - ( 1/3 + 1/6 + 1/10 + 1/15 + 1/21 + 1/28 + 1/36 + 1/45 )
A = 8 + 4/5
A = 44/5
Đúng 0
Bình luận (0)
A = 4/3 + 7/6 + 11/10 + 16/15 + 22/21 + 29/28 + 37/36 + 46/45
A = ( 1 + 1/3 ) + ( 1 + 1/6 ) + ( 1 + 1/10 ) + ( 1 + 1/15 ) + ( 1 + 1/21 ) + ( 1 + 1/28 ) + ( 1 + 1/36 ) + ( 1 + 1/45 )
A = ( 1 + 1 + 1 + ... + 1 ) - ( 1/3 + 1/6 + 1/10 + 1/15 + 1/21 + 1/28 + 1/36 + 1/45 )
Đúng 0
Bình luận (0)
giải hộ cho mik với
P=2-5/3+7/6-9/10+11/15-13/21+15/28-117/36+19/45-21/55
đúng mik sẽ tick cho
oi dòi ơi bấm máy tính mỏi tay lun:
=-194/99 nhá
Bạn ơi đừng nghiện nữa
:v mik không nghiện :>
Xem thêm câu trả lời
Tính nhanh: A=4/3+7/6+11/10+16/15+22/21+29/28+37/36+46/45
C= 2-\(\dfrac{5}{3}\)+\(\dfrac{7}{6}\)-\(\dfrac{9}{10}\)+\(\dfrac{11}{15}\)-\(\dfrac{13}{21}\)+\(\dfrac{15}{28}\)-\(\dfrac{17}{36}\)+\(\dfrac{19}{45}\)
tính C
\(=2-\left(\dfrac{5}{3}-\dfrac{7}{6}+\dfrac{9}{10}-...-\dfrac{19}{45}\right)\)
\(=2-2\left(\dfrac{5}{6}-\dfrac{7}{12}+\dfrac{9}{20}-...-\dfrac{19}{90}\right)\)
\(=2-2\left(\dfrac{1}{2}+\dfrac{1}{3}-\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}+\dfrac{1}{5}-...-\dfrac{1}{9}-\dfrac{1}{10}\right)\)
\(=2-2\cdot\dfrac{4}{10}=2-\dfrac{8}{10}=2-\dfrac{4}{5}=\dfrac{6}{5}\)
Đúng 1
Bình luận (0)
a) 7/-25+8/25 ; 4/5+4/-18 ; 7/21+9/-36
b) 12/20-2/5 ; 2/3-(-5/6) ; 6-3/20
c)2/21*(-7/3) ; 27/28*(-21) ; -15/7*(-14/25)
a) \(\dfrac{7}{-25}+\dfrac{8}{25}=\dfrac{-7}{25}+\dfrac{8}{25}=\dfrac{1}{25}\)
\(\dfrac{4}{5}+\dfrac{4}{-18}=\dfrac{4}{5+\left(-18\right)}=\dfrac{4}{-13}=\dfrac{-4}{13}\)
\(\dfrac{7}{21}+\dfrac{9}{-36}=\dfrac{1}{3}+\dfrac{1}{-4}=\dfrac{1}{3+\left(-4\right)}=\dfrac{1}{-1}=1\)
b) \(\dfrac{12}{20}-\dfrac{2}{5}=\dfrac{12}{20}+\left(\dfrac{-2}{5}\right)=\dfrac{3}{5}+\dfrac{-2}{5}=\dfrac{3+\left(-2\right)}{5}=\dfrac{1}{5}\)
\(\dfrac{2}{3}-\dfrac{-5}{6}=\dfrac{2}{3}+\dfrac{5}{6}=\dfrac{4}{6}+\dfrac{5}{6}=\dfrac{9}{6}=\dfrac{3}{2}\)
\(6-\dfrac{3}{20}=6+\dfrac{-3}{20}=\dfrac{60}{60}+\dfrac{-9}{60}=\dfrac{51}{60}\)
c) \(\dfrac{2}{21}.\dfrac{-7}{3}=\dfrac{2.\left(-1\right)}{7.3}=\dfrac{-2}{21}\)
\(\dfrac{27}{28}.\left(-21\right)=\dfrac{27.\left(-21\right)}{28}=\dfrac{-567}{28}\)
\(\dfrac{-15}{7}.\dfrac{-14}{25}=\dfrac{-3.\left(-2\right)}{1.5}=\dfrac{6}{5}\)
Đúng 0
Bình luận (0)
Tính nhẩm:
6 ´ 8 ..........
28 : 4 ..........
35 : 5 …….
7 ´ 9 ..........
56 : 7 ..........
4 ´ 6 ..........
5 ´ 4 ..........
42 : 6 ..........
36 : 6 …….
3 ´ 8 …….
45: 5 ……
49 :7 ……..
Đọc tiếp
Tính nhẩm:
6 ´ 8= .......... |
28 : 4 = .......... |
35 : 5 = ……. |
7 ´ 9 = .......... |
56 : 7 = .......... |
4 ´ 6 = .......... |
5 ´ 4 = .......... |
42 : 6 = .......... |
36 : 6 = ……. |
3 ´ 8 = ……. |
45: 5 = …… |
49 :7 = …….. |
6 ´ 8= 48 |
28 : 4 = 7 |
35 : 5 = 7 |
7 ´ 9 = 63 |
56 : 7 = 8 |
4 ´ 6 = 24 |
5 ´ 4 = 20 |
42 : 6 = 7 |
36 : 6 = 6 |
3 ´ 8 = 24 |
45: 5 = 9 |
49 :7 = 7 |
Đúng 0
Bình luận (0)
Tính
a)3-3^2+3^3-3^4+...+3^2011-3^2012+3^2013
b)7:11.12+7:12.13+...+7:59.60
c)1:21+1:28+1:36+1:45+1:55+1:66
d)1:5+1:45+1:117+...(biết D có 100 số hạng )
7 x 2 = ..... 7 x 4 = ..... 7 x 6 = ..... 7 x 3 = .....
2 x 7 = ..... 4 x 7 = ..... 6 x 7 = ..... 3 x 7 = .....
14 : 7 = ..... 28 : 7 = ..... 42 : 7 = ..... 21 : 7 = .....
14 : 2 = ..... 28 : 4 = ..... 42 : 6 = ..... 21 : 3 = .....
7 x 2 = 14 7 x 4 = 28 7 x 6 = 42 7 x 3 = 21
2 x 7 = 14 4 x 7 = 28 6 x 7 = 42 3 x 7 = 21
14 : 7 = 2 28 : 7 = 4 42 : 7 = 6 21 : 7 = 3
14 : 2 = 7 28 : 4 = 7 42 : 6 = 7 21 : 3 = 7
Đúng 0
Bình luận (0)