(Multiply 2) Quantitative subtraction (weight loss bucket) and light. To solve this problem, we usually start with the result of change.
Using the reciprocal relationship between multiplication and division and addition and subtraction, the reduction is carried out step by step. "meet the flowers in the shop three times and drink all the wine in the pot",
It can be seen that there is a barrel in the pot when the flowers meet three times, and there is a barrel of 1÷2 when the flowers meet three times, so there is 1 wine when the flowers meet twice.
2+1barrel, the second encounter shop has 2 barrels of wine (1÷ 2+1), so when it comes to flowers, there is wine (1÷ 2+1) 2+.
Barrel, once there is wine in the store, that is, the formula for calculating the original wine in the pot is
[(1÷ 2+1) ÷ 2+1] ÷ 2 = 7/8 (barrel)
So, the pot hit 7/8.
The key point of the above solution lies in inverse reduction, which can also be expressed by schematic diagram or line segment diagram.
Of course, if we use algebra to solve this problem, the quantitative relationship will be more clear. There are x barrels of wine in the pot. List the equations according to the meaning of the question.
2[2(2x- 1)- 1]- 1 = 0
X=7/8 (barrel) is obtained by solving.