You can
put this solution on YOUR website! Simply add up like terms:
4 lb 15 oz
+ 3 lb 13 oz
----------------
7 lb 28 oz
Since 16 oz = 1 lb, this means that 28 oz = 1 lb 12 oz (since 28=16+12). So 7 lb 28 oz breaks down to
7 lb 28 oz = 7 lb + (1 lb 12 oz) = 8 lb 12 oz
So the final answer is 8 pounds 12 ounces.