Specific operation: Step 1, weigh all seven bottles of medicine on the balance, with the total mass of A, A/7=b (as a comparison standard).

The second part, take a bottle of medicine at will, and weigh the total mass as B, with B/6 = C.

If c>, then the bottle of medicine you take is the one with five pills missing.

Analysis: If there are X pills per bottle, the average number of pills per bottle is M=(8x-5)/8=x-5/8.

If you take away five lost bottles and the rest are normal bottles, then the average number of bottles is X.

If you take a normal medicine bottle, the average number of pills per medicine bottle is N=(7x-5)/7=x-5/7.

Obviously, there is an x>M> noun (short for Noun).

(thinking: this is because the quality of each medicine is equal)

I think I learned the unary equation in the fifth grade of primary school, right? I hope my answer will be helpful to your child's study! Hey, if you don't understand, please tell me!