a) \(6^2:4\times3+2\times5^2\)
\(=36:4\times3+2\times25\)
\(=9\times3+50\)
\(=27+50\)
\(=77\)
b) \(125+70+375+230\)
\(=\left(125+375\right)+\left(70+230\right)\)
\(=500+300\)
\(=800\)
c) \(150:\left[25\times\left(18-4^2\right)\right]\)
\(=150:\left[25\times\left(18-16\right)\right]\)
\(=150:\left[25\times2\right]\)
\(=150:50\)
\(=3\)