Thực hiện phép tính (tính hợp lí nếu có thể): a) 7,84 + 1,837 + 5,163 + 0,16 b) (- 8,217) + 5,7 + (- 2,583) - 2,7 c) 4,35 - (2,67 - 1,65) + (3,54 - 6,33)

a) \(7,84 + 1,837 + 5,163 + 0,16\)

\( = \left( {7,84 + 0,16} \right) + \left( {1,837 + 5,163} \right)\)

\( = 8 + 7\)\( = 15.\)

c) \[4,35 - \left( {2,67 - 1,65} \right) + \left( {3,54 - 6,33} \right)\]

\[ = 4,35 - 2,67 + 1,65 + 3,54 - 6,33\]

\[ = \left( {4,35 + 1,65} \right) - \left( {2,67 + 6,33} \right) + 3,54\]

\[ = 6 - 9 + 3,54\]

\[ =  - 3 + 3,54\]

\[ = 0,54.\]

e) \(2,35:\left( { - 0,01} \right) + 7,6 \cdot \left( { - 1,25} \right)\)

\( = \left( { - 235} \right) + \left( { - 9,5} \right)\)

\( =  - 244,5.\)

g) \(14,65 \cdot 75 + 14,65 \cdot 40 + 14,65 \cdot \left( { - 15} \right)\)

\( = 14,65 \cdot \left[ {75 + 40 + \left( { - 15} \right)} \right]\)

\( = 14,65 \cdot 100\)

\( = 1\,\,465.\)

b) \(\left( { - 8,217} \right) + 5,7 + \left( { - 2,583} \right) - 2,7\)

\( = \left[ {\left( { - 8,217} \right) + \left( { - 2,583} \right)} \right] + \left( {5,7 - 2,7} \right)\)

\( =  - 10,8 + 3\)\( =  - 7,8.\)

d) \[2,63 \cdot 24,45 + 2,63 \cdot 75,55\]

\[ = 2,63 \cdot \left( {24,45 + 75,55} \right)\]

\[ = 2,63 \cdot 100\]

\[ = 263.\]

f) \(\left( { - 1,5} \right):\left( { - 0,1} \right) - {0,2^2} + 4,56 \cdot 9 + 9 \cdot 5,44\)

\( = 15 - 0,04 + \left( {4,56 \cdot 9 + 9 \cdot 5,44} \right)\)

\( = 14,96 + 9 \cdot \left( {4,56 + 5,44} \right)\)

\( = 14,96 + 9 \cdot 10\)

\( = 14,96 + 90\)

\( = 104,96.\)