Tinh gia tri bieu thuc
\(C=\frac{38}{45}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)\)
\(\frac{38}{45}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)\)
Biết lên mạng mà ko biết vào máy tính ak
Biết lên mạng mà ko biết vào máy tính ak
\(\frac{38}{45}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)\)
\(=\left(\frac{38}{45}-\frac{8}{45}\right)-\left(\frac{17}{51}-\frac{3}{11}\right)\)
\(=\frac{2}{3}-\frac{2}{33}\)
\(=\frac{20}{33}\)
Học tốt # ^-<
tính nhanh: \(\frac{38}{48}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)\)
\(\frac{38}{48}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)\)
\(=\frac{38}{48}-\left(-\frac{212}{495}\right)\)
\(=\frac{4831}{3960}\)
Tính nhanh :
\(A=\frac{38}{45}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)\)
\(B=\left(\frac{1}{2}+1\right).\left(\frac{1}{3}+1\right).\left(\frac{1}{4}+1\right)...\left(\frac{1}{99}+1\right)\)
\(A=\frac{38}{45}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)\)
\(A=\frac{38}{45}-\frac{8}{45}+\frac{17}{51}+\frac{3}{11}\)
\(A=\left(\frac{38}{45}-\frac{8}{45}\right)+\frac{1}{3}+\frac{3}{11}\)
\(A=\left(\frac{2}{3}+\frac{1}{3}\right)+\frac{3}{11}\)
\(A=1+\frac{3}{11}\)
\(A=\frac{11}{11}+\frac{3}{11}=\frac{14}{11}\)
\(B=\left(\frac{1}{2}+1\right).\left(\frac{1}{3}+1\right).\left(\frac{1}{4}+1\right)...\left(\frac{1}{99}+1\right)\)
\(B=\frac{3}{2}.\frac{4}{3}.\frac{5}{4}.\frac{6}{5}...\frac{100}{99}\)
\(B=\frac{3.4.5.6...100}{2.3.4.5...99}\)
\(B=\frac{100}{2}\)
\(B=50\)
a/\(\left(\frac{1}{3}+\frac{12}{67}+\frac{13}{41}\right)-\left(\frac{79}{67}-\frac{28}{41}\right)\)
b/ \(\frac{38}{45}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)\)
a)
\(\left(\frac{1}{3}+\frac{12}{67}+\frac{13}{41}\right)-\left(\frac{79}{67}-\frac{28}{41}\right)\)
= \(\frac{1}{3}+\frac{12}{67}+\frac{13}{41}-\frac{79}{67}+\frac{28}{41}\)
= \(\frac{1}{3}+\left(\frac{12}{67}-\frac{79}{67}\right)+\left(\frac{13}{41}+\frac{28}{41}\right)\)
= \(\frac{1}{3}+\left(-1\right)+1\)
= \(\frac{1}{3}+0=\frac{1}{3}\)
b)
\(\frac{38}{45}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)\)
= \(\frac{38}{45}-\frac{8}{45}+\frac{17}{51}+\frac{3}{11}\)
= \(\left(\frac{38}{45}-\frac{8}{45}\right)+\left(\frac{17}{51}+\frac{3}{11}\right)\)
= \(\frac{2}{3}+\frac{20}{33}\)
= \(\frac{14}{11}\)
Tinh hop ly gia tri cac bieu thuc sau
c) \(6\frac{5}{12}:2\frac{3}{4}+11\frac{1}{4}.\left(\frac{1}{3}-\frac{1}{5}\right)\)
d) \(\left(\frac{3}{5}+0,415-\frac{3}{200}\right).2\frac{2}{3}.0,25\)
bài 20 tính bằng phương pháp hợp lí nhất
a \(\frac{31}{23}-\left(\frac{7}{32}+\frac{8}{23}\right)\)
b \(\left(\frac{1}{3}+\frac{12}{67}+\frac{13}{41}\right)-\left(\frac{79}{67}-\frac{28}{41}\right)\)
c\(\frac{38}{45}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)\)
1) Tính hợp lý
a)\(\frac{31}{23}-\left(\frac{7}{32}+\frac{8}{32}\right)\)
b)\(\left(\frac{1}{3}+\frac{12}{67}+\frac{13}{41}\right)-\left(\frac{79}{67}-\frac{28}{41}\right)\)
c)\(\frac{38}{45}-\left(\frac{8}{45}-\frac{17}{51}-\frac{3}{11}\right)\)
d)\(\left(\frac{17}{28}+\frac{18}{29}-\frac{19}{30}-\frac{30}{31}\right).\left(-\frac{5}{12}+\frac{1}{4}+\frac{1}{6}\right)\)
Trả lời
b)(1/3+12/67+13/41)-(79/67-28/41)
=1/3+12/67+13/41-79/67+28/41
=1/3+(12/67-79/67)+(13/41+28/41)
=1/3+(-67/67)+41/41
=1/3+(-1)+1
=1/3+0
=1/3.
c)38/45-(8/45-17/51-3/11)
=38/45-8/45+17/51+3/11
=30/45+1/3+3/11
=2/3+1/3+3/11
=3/3+3/11
=1+3/11
=1 3/11.
d)(17/28+18/29-19/30-30/31).(-5/12+1/4+1/6)
=(17/28+18/29+19/30+30/31).(-5+3+2/12)
=(17/28+18/29+19/30+30/31).0
=0.
1) Tinh gia tri cua bieu thuc:
A=\(\frac{\left(1+2+...+100\right)\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{4}-\frac{1}{5}\right)\left(2,4.42-21.4,8\right)}{1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)
B=\(\frac{4^6.9^5+6^9.120}{-8^4.3^{12}+6^{11}}\)
\(A=\frac{\left(1+2+...+100\right)\left(\frac{1}{2}^2-...-\frac{1}{5}\right)\left(2,4.42-21.4,8\right)}{1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{100}}\)
=> \(A=\frac{\left(1+2+...+100\right)\left(\frac{1}{2}-...-\frac{1}{5}\right).0}{1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{100}}\)= 0
Tinh gia tri bieu thuc:
\(D=\left(\frac{3}{2}\right)^2+\left(\frac{1}{4}\right)^2-\left(\frac{1}{2}\right)^3\)
D = \(\frac{9}{4}+\frac{1}{16}-\frac{1}{8}\)
D = \(\frac{35}{16}\)
\(D=\left(\frac{3}{2}\right)^2+\left(\frac{1}{4}\right)^2-\left(\frac{1}{2}\right)^3\)
\(D=\frac{9}{4}+\frac{1}{16}-\frac{1}{8}\)
\(D=\frac{37}{16}-\frac{1}{8}\)
\(D=\frac{35}{16}.\)
Chúc bạn học tốt!