Tinh 6/7x12 + 6/12x17 + ...... +6/87 x 92 + 6/92 x95
mình se ra cau do thuong xuyen
Cho các số 56; 87; 59; 92; 84; 93; 35.
Hãy tìm ra 6 số trong 7 số trên có tổng chia hết cho 10.
Không có số nào có tổng chia hết cho 10 đâu bạn nhé
em ơi, em đdặt câu hỏi sai rồi, Ko có số nào chia hết cho 10 đc đâu. Nhưng 10 có thể chia đc 7 số trên nhưng là số thập phân( số có dấu phẩy )( mai sau lớp 5 thì em biết)
Cho các số 56; 87; 59; 92; 84; 93; 35.
Hãy tìm ra 6 số trong 7 số trên có tổng chia hết cho 10.
Giúp mk , mk gấp lắm
56+87+59+92+84+93+35=506 chia 10 dư 6
=>Muốn tìm tổng6 số chia hết cho 10 thì phải lấy tổng của 7 số này trừ đi số mà chia cho 10 có cùng số dư với tổng của 7 số
=>Số cần loại đi là 56
=>Tổng sẽ là 506-56=450
Tính hợp lí 92/2 + 93/6 + 87/12+ 79/20+69/30+57/42
Cho các số 56; 87; 59; 92; 84; 93; 35.
Hãy tìm ra 6 số trong 7 số trên có tổng chia hết cho 10.
Giúp mk chi tiết nhé
Cau 6 :
1) Tinh hop li : 127 + (- 18 ) + (-107) + (- 92 )
2) Tim x thuoc Z biet : [x - 3] - 7 = - 4
GUIP MINH NHA ! AI NHANH MINH K !
a) 127 + (-18) + (-107) + (-92)
=(-18 + -92) + 127 +(-107)
=(-37) + 127 + (-107)
=90 + (-107)
= -17
b) x- 3) -7= -4
x- 3 = (-4) + 7
x- 3 = 3
x = 3 + 3
x = 6
Vậy x = 6
bai 1 : hoc sinh khoi 6 cua truong khi xep hang 2 , 3 , 4 , 5 , 6 deu thua 1 em nhung khi xep hang 7 thi vua du . biet rang so hoc sinh khoi 6 it hon 350 . tinh so hoc sinh khoi 6
cac cau lam gi giai ro rang chi tiet nah cac cau ai nhanh nhat thi mink se tick cho nguoi do nha
A=5/1x6+5/6x11+5/11x16+5/16x21+...+5/101x106
B=3/1x4+3/4x7+3/7x10+....+3/97x100
C=1/2x7+1/7x12+1/12x17+....+1/97x102
D=1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
E=3/2x4+3/4x6+3/6x8+....+3/98x100
A = \(\dfrac{5}{1.6}\)+\(\dfrac{5}{6.11}\)+\(\dfrac{5}{11.16}\)+\(\dfrac{5}{16.21}\)+...+\(\dfrac{5}{101.106}\)
A = \(\dfrac{1}{1}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{11}+...+\dfrac{1}{101}-\dfrac{1}{106}\)
A = \(\dfrac{1}{1}\) - \(\dfrac{1}{106}\)
A = \(\dfrac{105}{106}\)
B = \(\dfrac{3}{1.4}\) +\(\dfrac{3}{4.7}\)+\(\dfrac{3}{7.10}\)+...+\(\dfrac{3}{97.100}\)
B = \(\dfrac{1}{1}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}-\dfrac{1}{10}+...+\dfrac{1}{97}-\dfrac{1}{100}\)
B = \(\dfrac{1}{1}\) - \(\dfrac{1}{100}\)
B = \(\dfrac{99}{100}\)
C = \(\dfrac{1}{2.7}+\dfrac{1}{7.12}\) + \(\dfrac{1}{12.17}\)+...+ \(\dfrac{1}{97.102}\)
C= \(\dfrac{1}{5}\) \(\times\)( \(\dfrac{5}{2.7}+\dfrac{5}{7.12}+\dfrac{5}{12.17}+...+\dfrac{5}{97.102}\))
C = \(\dfrac{1}{5}\)\(\times\)(\(\dfrac{1}{2}\) - \(\dfrac{1}{7}\) + \(\dfrac{1}{7}\) - \(\dfrac{1}{12}\) + \(\dfrac{1}{12}\) - \(\dfrac{1}{17}\)+...+ \(\dfrac{1}{97}\) - \(\dfrac{1}{102}\))
C = \(\dfrac{1}{5}\) \(\times\)( \(\dfrac{1}{2}\) - \(\dfrac{1}{102}\))
C = \(\dfrac{1}{5}\) \(\times\) \(\dfrac{25}{51}\)
C = \(\dfrac{5}{51}\)
D = \(\dfrac{1}{2}\) + \(\dfrac{1}{6}\) + \(\dfrac{1}{12}\) + \(\dfrac{1}{20}\) + \(\dfrac{1}{30}\) + \(\dfrac{1}{42}\) + \(\dfrac{1}{56}\) + \(\dfrac{1}{72}\)
D = \(\dfrac{1}{1.2}\) + \(\dfrac{1}{2.3}\) + \(\dfrac{1}{3.4}\) + \(\dfrac{1}{4.5}\) + \(\dfrac{1}{5.6}\) + \(\dfrac{1}{6.7}\)+\(\dfrac{1}{7.8}\)+ \(\dfrac{1}{8.9}\)
D = \(\dfrac{1}{1}\) - \(\dfrac{1}{2}\)+\(\dfrac{1}{2}\)-\(\dfrac{1}{3}\)+\(\dfrac{1}{3}\)-\(\dfrac{1}{4}\)+\(\dfrac{1}{4}\)-\(\dfrac{1}{5}\)+\(\dfrac{1}{5}\)-\(\dfrac{1}{6}\)+\(\dfrac{1}{6}\) - \(\dfrac{1}{7}\)+\(\dfrac{1}{7}\)-\(\dfrac{1}{8}\)+\(\dfrac{1}{8}\)-\(\dfrac{1}{9}\)
D = \(\dfrac{1}{1}\) - \(\dfrac{1}{9}\)
D = \(\dfrac{8}{9}\)
E = \(\dfrac{3}{2.4}\)+\(\dfrac{3}{4.6}\)+\(\dfrac{3}{6.8}\)+...+\(\dfrac{3}{98.100}\)
E = \(\dfrac{3}{2}\) \(\times\) ( \(\dfrac{2}{2.4}\) + \(\dfrac{2}{4.6}\)+ \(\dfrac{2}{6.8}\)+...+\(\dfrac{2}{98.100}\))
E = \(\dfrac{3}{2}\)\(\times\)( \(\dfrac{1}{2}\) - \(\dfrac{1}{4}\)+ \(\dfrac{1}{4}\) - \(\dfrac{1}{6}\)+\(\dfrac{1}{6}\)-\(\dfrac{1}{8}\)+...+\(\dfrac{1}{98}\) - \(\dfrac{1}{100}\))
E = \(\dfrac{3}{2}\) \(\times\) ( \(\dfrac{1}{2}\) - \(\dfrac{1}{100}\))
E = \(\dfrac{3}{2}\) \(\times\) \(\dfrac{49}{100}\)
E = \(\dfrac{147}{200}\)
\(\frac{92}{2}+\frac{93}{6}+\frac{87}{12}+\frac{79}{20}+\frac{69}{30}+\frac{57}{42}\)tính nhanh
\(42+\frac{93}{6}+\frac{87}{12}+\frac{79}{20}+\frac{69}{30}+\frac{57}{42}\)
\(=37+\left(1+\frac{93}{6}\right)+\left(1+\frac{87}{12}\right)+\left(\frac{79}{20}+1\right)+\left(1+\frac{69}{30}\right)+\left(1+\frac{57}{42}\right)\)
\(=37+\frac{99}{6}+\frac{99}{12}+\frac{99}{20}+\frac{99}{30}+\frac{99}{42}\)
\(=37+99\left(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}\right)\)
\(=37+99\left(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}\right)\)
\(=37+99\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}\right)\)
\(=37+99\left(\frac{1}{2}-\frac{1}{7}\right)\)
\(=37+99.\frac{5}{14}\)
\(=37+35\frac{5}{14}\)
\(=72\frac{5}{14}\)
92/6 x 72/15 : (-72)/10
\(\dfrac{92}{6}\times\dfrac{72}{15}:\left(-\dfrac{72}{10}\right)\)
\(=\dfrac{92\times72}{6\times15}:\left(-\dfrac{72}{10}\right)\)
\(=\dfrac{368}{5}:\left(-\dfrac{72}{10}\right)\)
\(=\dfrac{368}{5}\times\dfrac{-10}{72}\)
\(=\dfrac{368\times\left(-10\right)}{5\times72}\)
\(=\dfrac{-92}{9}\)
\(=\dfrac{92}{6}\cdot\dfrac{72}{15}\cdot\dfrac{-10}{72}=\dfrac{92}{6}\cdot\dfrac{-2}{3}=\dfrac{-92}{9}\)