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.