Simplify \(7\frac{1}{12}-4\frac{3}{4}+2\frac{1}{2}\)

Evaluate \(\frac{81.81+99.44}{20.09+36.16}\) correct to 3 significant figures.

A student spent 1/5 of his allowance on books, 1/2 of remainder on food and kept the rest for contingencies. What fraction was kept?

If \(p=\sqrt{\frac{rs^3}{t}}\), express r in terms of p, s and t?

Express the product of 0.21 and 0.34 in standard form