Решение:
a) $$2\frac{3}{10} = 2 + \frac{3}{10} = 2 + 0,3 = \mathbf{2,3}$$
б) $$3\frac{1}{10} = 3 + \frac{1}{10} = 3 + 0,1 = \mathbf{3,1}$$
в) $$6\frac{20}{100} = 6 + \frac{20}{100} = 6 + 0,20 = 6 + 0,2 = \mathbf{6,2}$$
г) $$7\frac{100}{1000} = 7 + \frac{100}{1000} = 7 + 0,100 = 7 + 0,1 = \mathbf{7,1}$$
д) $$21\frac{25}{1000} = 21 + \frac{25}{1000} = 21 + 0,025 = \mathbf{21,025}$$
e) $$45\frac{625}{10000} = 45 + \frac{625}{10000} = 45 + 0,0625 = \mathbf{45,0625}$$