\(53.25 - 25.12 + 75.53\)

\(= \left(\right. 53.25 + 75.53 \left.\right) - 25.12\)

\(= 53. \left(\right. 25 + 75 \left.\right) - 25.12\)

\(= 53.100 - 300\)

\(= 5300 - 300\)

\(= 5000\).

b) \(260 : \left[\right. 5 + 7. \left(\right. 72 : 2^{3} - 6 \left.\right) \left]\right. - 3^{2}\)

\(= 260 : \left[\right. 5 + 7. \left(\right. 72 : 8 - 6 \left.\right) \left]\right. - 9\)

\(= 260 : \left[\right. 5 + 7.3 \left]\right. - 9\)

\(= 260 : 26 - 9\)

\(= 10 - 9\)

\(= 1\).

 \(53.25 - 25.12 + 75.53\)

\(= \left(\right. 53.25 + 75.53 \left.\right) - 25.12\)

\(= 53. \left(\right. 25 + 75 \left.\right) - 25.12\)

\(= 53.100 - 300\)

\(= 5300 - 300\)

\(= 5000\).

b) \(260 : \left[\right. 5 + 7. \left(\right. 72 : 2^{3} - 6 \left.\right) \left]\right. - 3^{2}\)

\(= 260 : \left[\right. 5 + 7. \left(\right. 72 : 8 - 6 \left.\right) \left]\right. - 9\)

\(= 260 : \left[\right. 5 + 7.3 \left]\right. - 9\)

\(= 260 : 26 - 9\)

\(= 10 - 9\)

\(= 1\).

 \(53.25 - 25.12 + 75.53\)

\(= \left(\right. 53.25 + 75.53 \left.\right) - 25.12\)

\(= 53. \left(\right. 25 + 75 \left.\right) - 25.12\)

\(= 53.100 - 300\)

\(= 5300 - 300\)

\(= 5000\).

b) \(260 : \left[\right. 5 + 7. \left(\right. 72 : 2^{3} - 6 \left.\right) \left]\right. - 3^{2}\)

\(= 260 : \left[\right. 5 + 7. \left(\right. 72 : 8 - 6 \left.\right) \left]\right. - 9\)

\(= 260 : \left[\right. 5 + 7.3 \left]\right. - 9\)

\(= 260 : 26 - 9\)

\(= 10 - 9\)

\(= 1\).