301, 309, 312

$301.a)0.7\cdot0.89=0.623\approx0.62b)0.1\cdot0.15=0.015c)0.821\cdot0.6=0.4926\approx0.49306.a)0{,}9^7=0{,}4782969\approx0{,}48\approx48\%b)0{,}1^7=0{,}0000001\approx0{,}00000010\%307.a)0{,}74^3=0{,}405224\approx41\%b)0{,}74\cdot0{,}26^2=0{,}050024\approx5\%309.a)\frac{1}{4}=0.25b)\frac{2}{5}\cdot\frac{1}{4}=\frac{2}{20}=\frac{1}{10}=0{,}1312.a)0{,}15^3=0{,}003375=0{,}3375\%\approx0{,}34\%b)\left(1-0{,}15\right)^3=0{,}614125=61{,}4125\approx61\%c)1-0{,}614125=0{,}385875\approx39\%$