二4班48个同学参加体育活动，打球的有15个，踢球的有20个，剩下的跳绳，跳绳的有多少个？6O+G4h8j*c8S(J:b;o8E)r8t+G5Q
算式：提示-z9n8z*q.b7`,A7V3i)D)?7P6O+G4h8j*c8S(J:b;o8E)r8t+G5Q
答：跳绳的有;j*w-L7y个。6O+G4h8j*c8S(J:b;o8E)r8t+G5Q