What is mathematical reduction

What is mathematical reduction

When a clothing store buys a batch of clothes, half of the total number of pieces sold in the first month is less than 10 pieces, and the remaining half is more than 8 pieces in the second month. As a result, there are still 20 pieces left. How many pieces of clothes does the clothing store buy? The correct solution is: (20 + 8) x2-10 = 46, 46x2 = 92 test: (92 △ 2 + 10) /

There are 90 books in group A, B and C. After group B borrows three books from group A, it gives five books to group C. as a result, the three groups have the same number of books. Q: how many books did group A, B and C have?

A original 33, 32, C 25

When calculating the subtraction of two numbers, Xiao careless regarded 6 of the subtracted digit as 9 and 1 of the subtracted digit as 7. The result is 88. What is the correct result?

According to the meaning and analysis of the question, we can get: the difference increases: 9-6 = 3; the difference decreases: 70-10 = 60; 88 + 60-3 = 145

For a bag of salt, use 3 / 4 kg for the first time, use the remaining 3 / 4 for the second time, and there is still 1 kg left. How many kg is there in this bag of salt?

1 / (1-3 / 4) + 3 / 4 = 19 / 4, 19 / 4kg, that is 4.75kg