Question

#432
15
39-
+
1) 21
2)
19 4
+
20 5
-
5 3
1) +6층
7
10
3) 14-
+
4) 45-
19 4
+
20
5
2
5 8
+1=+
15 7 21
5)
6)
4
14
11
+6+
7 7
+3
8 18
16
33
8
15'
+2-

Answer 1

1)

$39\frac{15}{21} +(\frac{5}{7} +\frac{3}{5} )=39\frac{5}{7} +\frac{5}{7} +\frac{3}{5} =39\frac{10}{7} +\frac{3}{5} =40\frac{3}{7} +\frac{3}{5} =\\=40\frac{15}{35} +\frac{21}{35} =40\frac{36}{35} =41\frac{1}{35}$

2)

$(\frac{19}{20} +\frac{4}{5} )+6\frac{1}{6} =(\frac{19}{20} +\frac{16}{20} )+6\frac{1}{6}=\frac{35}{20} +6\frac{1}{6} =\frac{7}{4} +6\frac{1}{6} =\\=1\frac{3}{4} +6\frac{1}{6} =1\frac{9}{12} +6\frac{2}{12} =7\frac{11}{12}$

3)

$14\frac{7}{10}+(\frac{19}{20} +\frac{4}{5} )=14\frac{7}{10}+(\frac{19}{20} +\frac{16}{20} )=14\frac{7}{10}+\frac{35}{20} =14\frac{7}{10}+\frac{7}{4} =\\=14\frac{7}{10}+1\frac{3}{4}=14\frac{14}{20}+ 1\frac{15}{20} =15\frac{29}{20}=16\frac{9}{20}$

4)

$45\frac{2}{15} +(1\frac{5}{7} +\frac{8}{21} )=45\frac{2}{15} +(1\frac{15}{21} +\frac{8}{21} )=45\frac{2}{15} +1\frac{23}{21} =\\=45\frac{2}{15} +2\frac{2}{21} =45\frac{14}{105} +2\frac{10}{105} =47\frac{24}{105} =47\frac{8}{35}$

5)

$14\frac{9}{11} +(6+\frac{16}{33} )=14\frac{9}{11} +6\frac{16}{33} =14\frac{27}{33} +6\frac{16}{33} =20\frac{43}{33} =21\frac{10}{33}$

6)

$(\frac{7}{8} +3\frac{7}{18} )+2\frac{8}{15} =(\frac{63}{72} +3\frac{28}{72})+2\frac{8}{15}=3\frac{91}{72} +2\frac{8}{15}=\\=4\frac{19}{72} +2\frac{8}{15}=4\frac{95}{360} +2\frac{192}{360} =6\frac{287}{360}$