Answer:
Option (1)
Step-by-step explanation:
Option (1)
[tex]3\frac{3}{9}+7\frac{6}{11}=10\frac{87}{99}[/tex]
[tex]3\frac{3}{9}+7\frac{6}{11}[/tex] [tex]=3+\frac{3}{9}+7+\frac{6}{11}[/tex]
[tex]=(3+7)+(\frac{3}{9}+\frac{6}{11})[/tex]
[tex]=10+(\frac{3}{9}\times \frac{11}{11})+(\frac{6}{11}\times \frac{9}{9})[/tex]
[tex]=10+(\frac{33}{99}+\frac{54}{99})[/tex]
[tex]=10+\frac{87}{99}[/tex]
[tex]=10\frac{87}{99}[/tex]
True.
Option (2)
[tex]2\frac{3}{8}+6\frac{4}{5}=8\frac{12}{40}[/tex]
[tex]2\frac{3}{8}+6\frac{4}{5}=2+\frac{3}{8}+6+\frac{4}{5}[/tex]
[tex]=(2+6)+(\frac{3}{8}+\frac{4}{5})[/tex]
[tex]=(8)+(\frac{3}{8}\times \frac{5}{5} +\frac{4}{5}\times \frac{8}{8})[/tex]
[tex]=8+(\frac{15}{40}+\frac{32}{40})[/tex]
[tex]=8+\frac{47}{40}[/tex]
[tex]=8+\frac{40}{40}+\frac{7}{40}[/tex]
[tex]=8+1+\frac{7}{40}[/tex]
[tex]=9+\frac{7}{40}[/tex]
[tex]=9\frac{7}{40}[/tex]
False.
Option(3)
[tex]3\frac{3}{7}+4\frac{2}{3}=7\frac{2}{21}[/tex]
[tex]3\frac{3}{7}+4\frac{2}{3}=(3+\frac{3}{7})+(4+\frac{2}{3})[/tex]
[tex]=(3+4)+(\frac{3}{7}+\frac{2}{3})[/tex]
[tex]=7+(\frac{3}{7}\times \frac{3}{3} +\frac{2}{3}\times \frac{7}{7})[/tex]
[tex]=7+(\frac{9}{21}+\frac{14}{21})[/tex]
[tex]=7+(\frac{23}{21})[/tex]
[tex]=7+(\frac{21}{21}+\frac{2}{21})[/tex]
[tex]=8+\frac{1}{21}[/tex]
[tex]=8\frac{1}{21}[/tex]
False.
Option (4)
[tex]4\frac{5}{6}+5\frac{5}{7}=9\frac{10}{13}[/tex]
[tex]4\frac{5}{6}+5\frac{5}{7}=4+\frac{5}{6}+5+\frac{5}{7}[/tex]
[tex]=(4+5)+(\frac{5}{6}+\frac{5}{7})[/tex]
[tex]=9+(\frac{5}{6}\times \frac{7}{7}+\frac{5}{7}\times \frac{6}{6})[/tex]
[tex]=9+(\frac{35}{42}+\frac{30}{42})[/tex]
[tex]=9+\frac{65}{42}[/tex]
[tex]=9+(\frac{42}{42}+\frac{23}{42})[/tex]
[tex]=9+1+\frac{23}{42}[/tex]
[tex]=10\frac{23}{42}[/tex]
False.
Therefore, Option (1) is the answer.
