4 4/5 x 6 1/4 x 7/20

using the distributive property:

4 4/5 x 6 1/4 x 7/20
= (4 + 4/5) x (6 + 1/4) x 7/20
= ((4)(6) + (4/5)(6) + (4)(1/4) + (4/5)(1/4))(7/20)
= (24 + 24/5 + 1 + 1/5)(7/20)
= (25 + 25/5)(7/20)
= (25+5)(7/20)
= 30 * 7/20
= 210/20
= 21/2 = 10 1/2

or, using improper fractions,
4 4/5 x 6 1/4 x 7/20
= 24/5 x 25/4 x 7/20
= (24x25x7)/(5x4x20)
= 4200/400
= 21/2 = 10 1/2