One day and Sunday will be sunny.
My sister and I are having a good time, and my grandmother insists on calling me and asking me to settle her account.
Grandma bought 3 Jin 4 Liang eggs, 3 yuan and 50 cents per Jin. Grandma handed it in 12 yuan. How much should I get back? As soon as grandma's voice fell, grandpa said, "Change 1 minute!" I don't believe grandpa can calculate so fast, so I use the math knowledge I have learned to calculate: unit price multiplied by quantity = total price, money spent = change, exactly like grandpa's, and the change is 1 minute. I asked grandpa why he calculated so fast. It turns out that Grandpa divided 3 yuan's 5 angles into 3 yuan +5 angles, first calculate 3.4 times 3= 10.2 yuan, and then calculate 3.4 times 0.5. Half of 3.4 is 17 yuan, so a * * spent 1 1.9 yuan and paid 12 yuan, of course, a dime. After grandpa finished, I realized that he used multiplication and division.
Through this incident, I understand that mathematics can be used anywhere around us. Let mathematics serve us!
Example 2:
In the evening, I saw a problem in the Olympiad Book: the number of apple trees in the orchard is three times that of pear trees. Master Lao Wang fertilizes 50 apple trees and 20 pear trees every day. A few days later, all the pear trees were fertilized, but the remaining 80 apple trees were not fertilized. Excuse me: How many apple trees and pear trees are there in the orchard?
I am not intimidated by this question, but it can stimulate my interest. I think the apple tree is three times as big as the pear tree. If two kinds of trees are to be fertilized on the same day, Master Lao Wang will fertilize "20×3" apple trees and 20 pear trees every day. In fact, he only fertilizes 50 apple trees every day, which is 10, and the last 80 trees. Therefore, Master Lao Wang has been fertilizing for 8 days. 20 pear trees a day, 8 days is 160 pear trees. According to the first condition, there are 480 apple trees. This is to solve the problem with the idea of hypothesis, so I think the hypothesis method is really a good way to solve the problem.