解：∵A × A = A的平方 ， A + A = 2A ∴两个0.5的积 = 0.5 × 0.5 = 5/10 × 5/10 = 1/2 × 1/2 = 1/4 = 0.25 两个0.5的和 = 0.5 + 0.5 = 5/10 + 5/10 = 1/2 + 1/2 = 1 答：两个0.5的积是0.25，和是1
