\(a.35-17+1993-35-1993\\ =-17+\left(35-35\right)+\left(1993-1993\right)\\ =-17+0+0\\ =-17\\ b.-48725-\left(357-48725\right)+300\\ =-48725-357+48725+300\\ =\left(300-357\right)+\left(48725-48725\right)\\ =-57+0\\ =-57\\ c.3579-\left(49-5+3579\right)+49\\ =3579-49+5-3579+49\\ =5+\left(3579-3579\right)+\left(49-49\right)\\ =5+0+0\\ =5\)

a) \(35-17+1993-35-1993\)

\(=\left(35-35\right)+\left(1993-1993\right)-17\)

\(=-17\)

b) \(-48725-\left(357-48725\right)+300\)

\(=\left(-48725+48725\right)+\left(300-357\right)\)

\(=-57\)

c) \(3579-\left(49-5+3579\right)+49\)

\(=\left(3579-3579\right)+\left(49-49\right)+5\)

\(=5\)

Tính hợp lí:

a) 35-17+1993-35-1993

=(35-35)+(1993-1993)-17

=-17

b) -48725-(357-48725)+300

=-48725-357+48725+300

=-57

c) 3579-(49-5+3579)+49

=3579-49+5-3579+49

=5

a) \(\frac{3}{5}+\frac{6}{11}+\frac{7}{13}+\frac{2}{5}+\frac{16}{11}+\frac{19}{13}\)

\(=\left(\frac{3}{5}+\frac{2}{5}\right)+\left(\frac{6}{11}+\frac{16}{11}\right)+\left(\frac{7}{13}+\frac{19}{13}\right)\)

\(=1+2+2=5\)

b) \(\frac{1995}{1997}x\frac{1990}{1993}x\frac{1997}{1994}x\frac{1993}{1995}x\frac{997}{995}=\frac{1995x1990x1997x1993x997}{1997x1993x1994x1995x995}=\frac{1990x997}{1994x995}=\frac{995x2x997}{997x2x995}=1\)

a) =(3/5+2/5)+(6/11+16/11)+(19/13+7/13)

=5/5+22/11+26/13

=1+2+3

=6

\(\frac{15}{25}=\frac{3\cdot5}{5\cdot5}=\frac{3}{5}=\frac{21}{35}< \frac{25}{35}=\frac{5\cdot5}{5\cdot7}=\frac{5}{7}\)

\(\frac{17}{49}< \frac{17}{48}< \frac{18}{48}=\frac{3\cdot6}{6\cdot8}=\frac{3}{8}\)

\(\frac{13}{60}< \frac{13}{50}=\frac{26}{100}< \frac{27}{100}\)

\(\frac{43}{47}>\frac{42}{47}>\frac{42}{49}=\frac{6\cdot7}{7\cdot7}=\frac{6}{7}=\frac{30}{35}>\frac{29}{35}\)

\(\frac{1993}{1995}< \frac{1994}{1996}=\frac{997}{998}\)

Đáp án là 24

35.13+35.17+65.75-65.45

=35.(13+17)+65.(75-45)

=35.30+65.30

=30.(35+65)

=30.100

=3000

\(=\left(\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{6}\right)+\left(\dfrac{2}{5}+\dfrac{-4}{35}+\dfrac{5}{7}\right)+\dfrac{1}{41}=1+1+\dfrac{1}{41}=\dfrac{83}{41}\)

a ] bằng1

bằng 5 cơ