Topic content:
If the height of the desk is 2 mm higher than the standard height, it will be recorded as+2 mm. If it is 3 mm lower than the standard height, what will be recorded as
There are five desks, and their dimensions are 1 mm, - 1 mm, 0 mm,+3 mm, - 1.5 mm longer than the standard dimensions. If it is specified that the height of the desks should not be 2 mm higher than the standard height at the highest and 2 mm lower than the standard height at the lowest, it is qualified. How many desks are unqualified?
Best answer:
-3mm, 1 unqualified
Answer analysis:
Judgement can be made according to the relativity of positive and negative numbers
The height of the desk 2 mm higher than the standard height is recorded as+2 mm, and the height 3 mm lower than the standard height is recorded as - 3 mm.
One of the above five desks is unqualified
Comment: Conceptual questions are the basis of mathematics learning, which is very important. However, such questions often have independent knowledge points, so they are not very common in the middle school entrance examination. They often appear in the form of blank filling questions and multiple-choice questions. They are basic questions with ordinary difficulty
Test core:
Positive Number: negative number (real number) greater than 0: negative number (real number) less than 0 is neither positive nor negative.
Non negative number: positive number and zero. Non positive number: negative number and zero.