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a: \(=\dfrac{2}{3}+\dfrac{19}{35}=\dfrac{70+57}{105}=\dfrac{127}{105}\)
b: \(=\dfrac{2}{7}+\dfrac{2}{5}=\dfrac{24}{35}\)
c: \(=\dfrac{7}{12}-\dfrac{14}{2}=\dfrac{7-84}{12}=\dfrac{-77}{12}\)
d: \(=\dfrac{-15}{60}-\dfrac{1}{8}=-\dfrac{3}{8}\)
e: \(=-\dfrac{12}{72}+\dfrac{1}{18}=\dfrac{-3}{18}+\dfrac{1}{18}=\dfrac{-2}{18}=\dfrac{-1}{9}\)
1+2+3+4+5+6+7+8+9+10=55
11+12+13+14+15+16+17+18+19+20=155
1+2+3+4+5+6+7+8+9+10+11+12+13+14 +15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30-50-53=362
\(1+2+3+4+5+6+7+8+9+10=55\)
\(11+12+13+14+15+16+17+18+19+20=155\)
1: =72/90+65/90=137/90
2: =24/56-77/56=-53/56
3: =-7/10+4/5=1/10
4: =15/100-4/100=11/100
5: =4/6-5/6=-1/6
6: =10/40-15/40-76/40=-81/40
7: =-9/10+7/18
=-81/90+35/90=-46/90=-23/45
8: =27/90-55/90=-28/90=-14/45
9: =36/60-50/60-35/60=-49/60
10: =-4/9+5/6-3/8
=-32/72+60/72-27/72
=1/72
a: =2/3+2/7=14/21+6/21=20/21
b: =17/18-33/18=-16/18=-8/9
c: =7/12-3/14=49/84-18/84=31/84
d: =-1/4-1/8=-3/8