3 )
a )
[tex]( \dfrac{13}{40} + \dfrac{3}{15} + \dfrac{7}{30} ) + ( \dfrac{7}{40} + \dfrac{3}{30} + \dfrac{2}{15} ) = \\ \\ \\ ( \dfrac{13}{40} + \dfrac{7}{40} ) + ( \dfrac{3}{15} + \dfrac{2}{15} ) + ( \dfrac{7}{30} + \dfrac{3}{30} ) = \\ \\ \\ \dfrac{20}{40}^{ \div 20} + \dfrac{5}{15}^{ \div 5} + \dfrac{10}{30}^{ \div 10} = \\ \\ \\ \dfrac{1}{2}^{ \times 3} + \dfrac{1}{3}^{ \times 2} + \dfrac{1}{3}^{ \times 2} = \\ \\ \\ \dfrac{3}{6} + \dfrac{2}{6} + \dfrac{2}{6} = \dfrac{7}{6} [/tex]
b )
[tex]( 2\dfrac{1}{14} + 1 \dfrac{3}{7}) + ( \dfrac{5}{4} + \dfrac{6}{14}) + ( \dfrac{4}{7}^{ \times 2} + \dfrac{7}{4}) = \\ \\ \\ ( \dfrac{29}{14} + \dfrac{10}{7} ^{ \times 2} ) +( \dfrac{5}{4} + \dfrac{6}{14} ) + ( \dfrac{8}{14} + \dfrac{7}{4} ) = \\ \\ \\ \dfrac{29 +20 + 6 + 8}{14} + \dfrac{5 + 7}{4} = \\ \\ \\ \dfrac{63}{14}^{ \div 7} + \dfrac{12}{4}^{ \div 4} = \\ \\ \\ \dfrac{9}{2} + \dfrac{3}{1}^{ \times 2} = \dfrac{9}{2} + \dfrac{6}{2} = \dfrac{15}{2} [/tex]
4 )
a )
[tex] \dfrac{56}{55}^{ \times 64} ( > ) \dfrac{65}{64}^{ \times 55} \\ \\ \\ \dfrac{3584}{3520} ( > ) \dfrac{3575}{3520} [/tex]
b )
[tex] \dfrac{68}{66}^{ \times 76} ( > ) \dfrac{78}{76}^{ \times 66} \\ \\ \\ \dfrac{5168}{5016} ( > ) \dfrac{5148}{5016} [/tex]
c )
[tex] \dfrac{124}{123}^{ (141} ( > ) \dfrac{142}{141}^{(123} \\ \\ \\ \dfrac{17484}{17343} ( > ) \dfrac{17466}{17343} [/tex]
d )
[tex] \dfrac{2012}{2011}^{(2012} () \dfrac{2013}{2012} ^{(2011} \\ \\ \\ 2012 \times 2012 \neq 2011 \times 2013 \\ \\ \\ 4048144\neq4048143 \\ \\ \\ \dfrac{4048144}{4046132} ( > ) \dfrac{4048143}{4046132} [/tex]
