1. Use the characteristics of decimals and fractions to realize the conversion of decimals and fractions.
When learning Xi decimal in Primary 5, we knew:
A decimal place, the unit of counting is a tenth, in other words, a decimal place represents a tenth;
Two decimal places, counting in hundredths, in other words, one decimal place indicates the hundredth;
.And so on.
Therefore, the decimal can be directly converted to the denominator according to the number of digits after the decimal point, and then according to the nature of the score, it can be reduced to the simplest score.
Well, 14The process of turning 4 into fractions is shown in the figure below:
Second, the use of one-dimensional equations to realize the conversion of decimals and fractions.
We know that the standard form of a univariate equation:ax=b, when a≠0, there is a unique solution b a(fraction),Therefore, the form of equation can be used to realize the conversion of decimal and fraction.
Set 144=x
Multiply both sides of the equation by 10 to get 10x=144
Solution:
Some people may think that I am complicating a simple problem by using a unary equation, but in fact, decimals are divided into finite and infinite, and for finite decimals, the first method may be simpler;For infinite cyclic decimals, only a one-dimensional equation can be used, while infinite non-cyclic decimals cannot be converted into fractions.
Example 1:
Example 2:
Isn't it easy to use a one-dimensional equation to convert decimals into fractions?Isn't it useful to learn unary equations?
Unary equations are the key content of junior high school mathematics, and the applicable question types are also particularly rich, especially the application problems, which need children to learn Xi carefully and focus on grasping.
If you feel that your child is weak in this area, you should learn more when you have time, and you will always pass the test.