Jada is buying 4 stamps that cost $0.49 each. how can rounding be used to estimate the total cost of the stamps?
since each stamp is about $0.50, the total cost is approximately 4 + 0.5 $4.50.
since she is buying about 10 stamps, the total cost is approximately 10 × 0.49 = $4.90.
since each stamp is about $0.50, the total cost is approximately 4 x 0.5 = $2.00.
since she is buying about 10 stamps, the total cost is approximately 10 +0.49 = $10.49.

Acompany produces packets of soap powder labeled “giant size 32 ounces.” the actual weight of soap powder in such a box has a normal distribution with a mean of 33 oz and a standard deviation of 0.7 oz. to avoid having dissatisfied customers, the company says a box of soap is considered underweight if it weighs less than 32 oz. to avoid losing money, it labels the top 5% (the heaviest 5%) overweight. how heavy does a box have to be for it to be labeled overweight?