How time flies! The animal school will have a final exam soon. On this day, the giraffe teacher came into the classroom with a stack of test papers and distributed them to the students. After the students got the test paper, they all bowed their heads and wrote, and the little white rabbit was no exception. These questions are simply too simple for the clever white rabbit.
The white rabbit finished the examination paper three times, five times and two times. It proudly looked at the little turtle who was still slowly answering questions at the same table, and then proudly handed the test paper to the giraffe teacher.
However, when the test paper was handed out, the little white rabbit was unhappy.
The tortoise, which usually looks stupid, got 100 this time, while the clever white rabbit only got 99 points. Why is this happening? Because the white rabbit made a mistake in filling in the blank, one point was deducted. What is the problem that bothers the little white rabbit? This fill-in-the-blank problem is like this: move the decimal point 40 to the left () and then to the right, and the two digits are 0. 04。
The little white rabbit was so careless that he only read the first part of the topic. As a result, the topic became: moving the decimal point of 40 to the left () is 0. 04。 During the exam, the little white rabbit missed the words "move two places to the right again" and filled in "three places" in brackets.
So, can the careless little white rabbit do this problem after all? Teacher giraffe seriously asked the little white rabbit to do it again. The white rabbit thought about it and filled in the correct answer "5 digits" in brackets.
At this time, Teacher Giraffe praised Little Turtle for his earnest examination, serious problem solving, good learning attitude and great progress, and encouraged Little Turtle to explain the thinking method of this problem to everyone. "In fact, this problem can be reversed. Put 0 first. The decimal point of 04 is shifted two places to the left to get 0. 0004, count to 0. 0004 is restored to 40, how many digits does the decimal point need to be moved to the right? " The little turtle counted slowly. "There are five places moved here. Because it is the other way around, the correct answer should be to move the decimal point 40 to the left (five places) and then move it to the right by two places to get 0. 04。 You can also think about this problem like this. First move the decimal point 40 to the right to get 4000, and then move it to the left (5 digits) to equal 0. 04。 "
In the face of the carefully explained little turtle, the little white rabbit realized with regret that there were many "traps" hidden in this math problem, and it was easy to fall into it if you were not careful. You can't make this mistake again in the future.
Label: talk