Tính: 63 + 3.62 + 33 / -13
Tính giá trị của biếu thức sau: 6 3 + 3 . 6 2 + 3 3 - 13
Tìm giá trị của biểu thức sau
a) 42.4321042.43210
b) (0,6)5(0,2)6(0,6)5(0,2)6
c)27.9365.8227.9365.82
d) 63+3.62+33−13
Biết: 13+23+33+....+103=3025. Tính S= 23+43+63+...+203
huỳnh thị ngân hà, nau te, trần như tính sao ra z?
S = 13+10+23+20+33+30+...+103+100
S = 13+23+33+...+103+10.100
S = 3025+1000
S = 4025
6020 , chắc chắn đúng 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000%
Tính hợp lí:
B = (-1) + (-4) + (-7) + (-10) + ... + (-100)
C = (-13) + 23 + (-33) + 43 + (-53) + 63 +...+ (-93) + (-103)
\(B=-\left(1+4+7+...+100\right)\\ B=-\dfrac{\left(100+1\right)\left[\left(100-1\right):3+1\right]}{2}=-\dfrac{101\cdot34}{2}=-1717\\ C=10+10+10+10-103=50-103=-53\)
tính nhanh:
1/3 + 13/15 + 33/35 + 61/63 + 97/99 + 141/143
\(\frac{1}{3}+\frac{13}{15}+\frac{33}{35}+\frac{61}{63}+\frac{97}{99}\)\(+\frac{141}{143}\)
\(=\left(1-\frac{2}{3}\right)+\left(1-\frac{2}{15}\right)\)\(+\left(1-\frac{2}{35}\right)+\left(1-\frac{2}{63}\right)\)\(+\left(1-\frac{2}{99}\right)+\left(1-\frac{2}{143}\right)\)
\(=\left(1+1+1+1+1+1\right)-\)\(\left(\frac{2}{3}+\frac{2}{15}+\frac{2}{35}+\frac{2}{63}+\frac{2}{99}+\frac{2}{143}\right)\)
\(=6-\)\(\left(\frac{2}{1\times3}+\frac{2}{3\times5}+\frac{2}{5\times7}+\frac{2}{7\times9}+\frac{2}{9\times11}+\frac{2}{11\times13}\right)\)
\(=6-\)\(\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}+\frac{1}{11}-\frac{1}{13}\right)\)
\(=6-\left(1-\frac{1}{13}\right)\)
\(=6-\frac{12}{13}\)
\(=\frac{66}{13}\)
Tính
1/3+13/15+33/35+61/63+97/99+141/143
Tính
1/3+13/15+33/35+61/63+97/99+141/143
giúp mình nha! ^_^
\(\frac{1}{3}+\frac{13}{15}+\frac{33}{35}+\frac{61}{63}+\frac{97}{99}+\frac{141}{143}\)
\(=\left(1-\frac{2}{3}\right)+\left(1-\frac{2}{15}\right)+\left(1-\frac{2}{35}\right)+\left(1-\frac{2}{63}\right)+\left(1-\frac{2}{99}\right)+\left(1-\frac{2}{143}\right)\)
\(=\left(1+1+1+1+1+1\right)-\left(\frac{2}{3}+\frac{2}{15}+\frac{2}{35}+\frac{2}{63}+\frac{2}{99}+\frac{2}{143}\right)\)
\(=6-\left(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}+\frac{2}{11.13}\right)\)
\(=6-\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}+\frac{1}{11}-\frac{1}{13}\right)\)
\(=6-\left(1-\frac{1}{13}\right)\)
\(=6-\frac{12}{13}\)
\(=\frac{66}{13}\)
Ủng hộ mk nha ^_-
7/3*13+ 7/13*23+ 7/23*33+ 7/33*43+ 7/43*53+ 7/53*63
\(A=\frac{7}{3\times13}+\frac{7}{13\times23}+...+\frac{7}{53\times63}\)
\(A=\frac{7}{10}.\left[\left(\frac{1}{3}-\frac{1}{13}\right)+\left(\frac{1}{13}-\frac{1}{23}\right)+....+\left(\frac{1}{53}-\frac{1}{63}\right)\right]\)
\(A=\frac{7}{10}.\left(\frac{1}{3}-\frac{1}{13}+\frac{1}{13}-\frac{1}{23}+....+\frac{1}{53}-\frac{1}{63}\right)\)
\(A=\frac{7}{10}.\left(\frac{1}{3}-\frac{1}{63}\right)\)
\(A=\frac{7}{10}.\frac{20}{63}\)
\(A=\frac{2}{9}\)
Tính hợp lí:
A = 1 + (-2) + 3 + (-4) + 5 +(-6) + ... + 99 + (-100)
B = (-1) + (-4) + (-7) + (-10) +...+ (-100)
C = (-13) + 23 + (-33) + 43 + (-53) + 63 +...+ (-93) + 103
mik làm 1 câu thôi các cau khác 1 chang lun chỉ khác số
A = 1 + (-2) + 3 + (-4) + 5 +(-6) + ... + 99 + (-100)
A=(1+(-2))+(3+(-4))+.....+(99+(-100))
A=(-1)+(-1)+......+(-1) CÓ 50 SỐ
A= -50