Odpowiedź
a.
[tex]\displaystyle{ 3 \frac {1} {6} - 1 \frac {3} {4} \: = \: \frac {19} {6} - \frac {7} {4}} \: =}\\\\\\\displaystyle{ \frac {19 \cdot 4} {6 \cdot 4} - \frac {7 \cdot 6} {4 \cdot 6}} \: =}\\\\\\\displaystyle{ \frac {76} {24} - \frac {42} {24}} \: = \: \frac {76 - 42} {24}} \: =}\\\\\\\\\displaystyle{ \frac {34} {24} \: = \: \frac {17} {12}} \: = \: 1 \frac {5} {12}}[/tex]
b.
[tex]\displaystyle{ 2 \frac {4} {5} - (-1,\!75) \: = \: 2 \frac {4} {5} + 1,\!75 \: =}\\\\\\\displaystyle{ 2 \frac {4 \cdot 20} {5 \cdot 20} + 1,\!75 \: = 2 \frac {80} {100} + 1,\!75 \: =}\\\\\\\displaystyle{ 2,\!80 + 1,\!75 \: = \: \boxed{ \:\:4,\!55 \:\: } \: = \: 4 \frac {55} {100} \: = \: \boxed{ \:\:4 \frac {11} {20} \:\:}}[/tex]
c.
[tex]\displaystyle{ -1 \frac {1} {7} + (-2 \frac {1} {3} ) =}\\\\\\\displaystyle{ - \, \frac {7 + 1} {7} - \frac {6 + 1} {3} =}\\\\\\\displaystyle{ - \, \frac {8} {7} - \frac {7} {3} =}\\\\\\\displaystyle{ - \, \frac {8 \cdot 3} {7 \cdot 3} - \frac {7 \cdot 7} {3 \cdot 7} =}\\\\\\\displaystyle{ - \, \frac {24} {21} - \frac {49} {21} =}\\\\[/tex]
[tex]\displaystyle{ \frac {- 24 - 49} {21} = \frac {-73} {21} = \frac {-63 \,- 10} {21} = -3 \frac {10} {21} }[/tex]
d.
[tex]\displaystyle{ \frac {0,\!12} { \:\: -0,\!4 \:\: } = } \displaystyle{ \frac {\displaystyle{ \frac {12} {100} }} { \:\: \displaystyle{ \frac {-4} { \: 100 \: } } \:\: } = } \displaystyle{ \frac {12} { \:\: -4 \:\: } = \frac { \:\: -12 \:\: } { \:\: 4 \:\: } \: = \: -3}[/tex]
e.
[tex]\displaystyle{ \frac {-4,\!5} {\displaystyle{ 2 \frac {4} {7} } } } \: = \:\displaystyle{ \frac {\displaystyle{ \frac { \: -45 \: } {10} }} {\displaystyle{ \frac {14 + 4} {7} } } } \: = \:\displaystyle{ \frac {\displaystyle{ \frac { \: -45 \: } {10} }} {\displaystyle{ \frac {18} {7} } } } \: = \:\displaystyle{ \frac {\displaystyle{ \frac { \: -45 \: } {10} \cdot ( 7 \cdot 10 )}} {\displaystyle{ \frac {18} {7} \cdot ( 7 \cdot 10 )} } } \: = \:[/tex]
[tex]\displaystyle{ \frac { \:\: -45 \cdot 7 \:\: } {18 \cdot 10} \: = \: }\displaystyle{ \frac { \:\: -5 \cdot 9 \cdot 7 \:\: } {9 \cdot 2 \cdot 2 \cdot 5} \: = \: }\displaystyle{ \frac { \:\: -7 \:\: } {2 \cdot 2} \: = \: }\displaystyle{ \frac { \:\: -7 \:\: } {4} \: = \: }\displaystyle{ \frac { \:\: -4 - 3 \:\: } {4} \: = \: -1 \frac {3} {4}}[/tex]
Szczegółowe wyjaśnienie
Znaki w punkcie a. są raz tak, a raz inaczej. Więc na wszelki wypadek poniżej umieściłam drugą wersję
[tex]\displaystyle{ - 3 \frac {1} {6} + 1 \frac {3} {4} \: = \: \frac {-19} {6} + \frac {7} {4}} \: =}\\\\\\\displaystyle{ \frac {-19 \cdot 4} {6 \cdot 4} + \frac {7 \cdot 6} {4 \cdot 6}} \: =}\\\\\\\displaystyle{ \frac {-76} {24} + \frac {42} {24}} \: = \: \frac {-76 + 42} {24}} \: =}\\\\\\\\\displaystyle{ \frac {-34} {24} \: = \: \frac {-17} {12}} \: = \: -1 \frac {5} {12}}[/tex]
W punkcie c. odgadywałam co tam naprawdę miało być...