Let's convert 8 pounds and 3 ounces, into all ounces.
So we know one pound = 16 ounces.
1 lb = 16 oz.
Now since Omar is 8 pounds + 3 ounces, we multiply 16 by 8, and add on the 3:
16 * 8 = 128
128 + 3 = 131
So Omar weights 131 ounces when he was born.
Now Omar has to gain 5 ounces each week, for 4 weeks. This means in total, he'll have to gain 5*4=20 ounces in 4 weeks.
Add them together:
131 + 20 = 151 oz OR 9 7/16 lb.
