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\(\left(\frac{3}{4}+\frac{2}{11}-\frac{8}{13}\right)+\left(\frac{1}{4}-\frac{5}{13}\right)\)
\(=\frac{3}{4}+\frac{2}{11}-\frac{8}{13}+\frac{1}{4}-\frac{5}{13}\)
\(=\left(\frac{3}{4}+\frac{1}{4}\right)+\frac{2}{11}-\left(\frac{8}{13}+\frac{5}{13}\right)\)
\(=1+\frac{2}{11}-1\)
\(=\frac{2}{11}\)
\(\left(\frac{9}{53}+\frac{21}{31}\right)+\left(\frac{44}{53}-\frac{16}{7}\right)+\frac{10}{31}\)
\(=\frac{9}{53}+\frac{21}{31}+\frac{44}{53}-\frac{16}{7}+\frac{10}{31}\)
\(=\left(\frac{9}{53}+\frac{44}{53}\right)+\left(\frac{21}{31}+\frac{10}{31}\right)-\frac{16}{7}\)
\(=1+1-\frac{16}{7}\)
\(=2-\frac{16}{7}\)
\(=\frac{14}{7}-\frac{16}{7}\)
\(=\frac{-2}{7}\)
\(\text{Phần a nên sửa đề thế này :}\) \(\frac{1}{7}.\frac{-3}{8}+\frac{1}{7}.\frac{-13}{8}\)
\(\text{Giải :}\)
\(\frac{1}{7}.\frac{-3}{8}+\frac{1}{7}.\frac{-13}{8}\)
\(=\frac{1}{7}\left(\frac{-3}{8}+\frac{-13}{8}\right)\)
\(=\frac{1}{7}.\left(-2\right)\)
\(=\frac{-2}{7}\)
\(\frac{3}{5}.\frac{13}{46}-\frac{1}{10}.\frac{16}{23}\)
\(=\frac{3}{5}.\left(\frac{1}{46}.13\right)-\frac{1}{10}.\frac{32}{46}\)
\(=\left(\frac{3}{5}.13\right).\frac{1}{46}-\left(\frac{1}{10}.32\right).\frac{1}{46}\)
\(=\frac{39}{5}.\frac{1}{46}-\frac{32}{10}.\frac{1}{46}\)
\(=\frac{78}{10}.\frac{1}{46}-\frac{32}{10}.\frac{1}{46}\)
\(=\left(\frac{78}{10}-\frac{32}{10}\right).\frac{1}{46}\)
\(=\frac{46}{10}.\frac{1}{46}\)
\(=\frac{1}{10}\)
b,1×2×3×...×9-1×2×3×...×8-1×2×3×...×7×8^2
=(1×2×3×...×8)×(9-1-8)
=(1×2×3×...×8)×0
=0
\(a)-\left(\frac{3}{10}-\frac{6}{11}\right)-\left(\frac{21}{30}-\frac{5}{11}\right)\)
\(=-\frac{3}{10}+\frac{6}{11}-\frac{21}{30}+\frac{5}{11}\)
\(=\left(-\frac{3}{10}-\frac{21}{30}\right)+\left(\frac{6}{11}+\frac{5}{11}\right)\)
\(=-1+1\)
\(=0\)
\(b)\left(\frac{13}{5}+\frac{7}{16}\right)-\left(\frac{11}{16}-\frac{12}{10}\right)\)
\(=\frac{13}{5}+\frac{7}{16}-\frac{11}{16}+\frac{12}{10}\)
\(=\left(\frac{13}{5}+\frac{12}{10}\right)+\left(\frac{7}{16}-\frac{11}{16}\right)\)
\(=\frac{19}{5}+\left(-\frac{1}{4}\right)\)
\(=\frac{71}{20}\)
a) \(-\left(\frac{3}{10}-\frac{6}{11}\right)-\left(\frac{21}{30}-\frac{5}{11}\right)\)
\(=\frac{-3}{10}+\frac{6}{11}-\frac{21}{30}+\frac{5}{11}\)
\(=\left(\frac{-3}{10}-\frac{21}{30}\right)+\left(\frac{6}{11}+\frac{5}{11}\right)\)
\(=\left(\frac{-9}{30}-\frac{21}{30}\right)+1\)
\(=-1+1\)
= 0
b) \(\left(\frac{13}{5}+\frac{7}{16}\right)-\left(\frac{11}{16}-\frac{12}{10}\right)\)
\(=\frac{13}{5}+\frac{7}{16}-\frac{11}{16}+\frac{12}{10}\)
\(=\left(\frac{13}{5}+\frac{12}{10}\right)+\left(\frac{7}{16}-\frac{11}{16}\right)\)
\(=\left(\frac{26}{10}+\frac{12}{10}\right)-4\)
= \(\frac{19}{5}-4\)
= \(\frac{-1}{5}\)
Bài làm
13 - 12 + 11 + 10 -9 +8 - 7 - 6 + 5 - 4 + 3 +2 -1
= 1 + 11+ 1 + 1 - 6 + 1 + 3 + 1
= 15 - 11
= 4
# Chúc bạn học tốt #
13-12+11+10-9+8-7-6+5-4+3+2-1
=(13-12)+(11-6)+(10-9)+(8-7)+(5-4)+(2-1)+3
=1+5+1+1+1+1+3
=13
mn vô đây xem thằng Phạm Việt Đức chửi tớ nek
Giúp tôi giải toán - Hỏi đáp, thảo luận về toán học - Học toán với OnlineMath
13-12+11+10-9+8-7-6+5-4+3+2-1
=13-(12+1) -(11+2)-(10+3)-(9+4)-(8+5) +(7+6)
=13-13-13-13-13-13+13
=0-0-0-0-0-0+13
=0+13
=13
= ( 13 -12 ) + 11 + ( 10 - 9 ) + ( 8 - 7-6 + 5 ) + ( 3 + 2 - 4 ) -1
= 1 + 11 + 1 + 0 + 1 - 1
= 13 + 0
= 13
13 - 12 + 11 + 10 - 9 + 8 - 7 - 6 + 5 - 4 + 3 + 2 - 1 = 9
\(=\left(-17\right)\cdot3=-51\)