Recently, some students don't quite understand why we should use equations to solve such a simple problem as "a number plus 12 equals 20".
In fact, equation is a different problem-solving method from what we have learned before, especially it is very convenient to solve some difficult and reverse thinking problems. For such a simple problem as "a number plus 12 equals 20", it is impossible to show the advantages of the equation by solving it, but now we are learning a new method and mastering a new tool.
For example, A and B used to have the same number of sheep. A year later, the number of sheep in family A increased five times, and the number of sheep in family B increased nine times. Now there are 420 sheep in two families. How much do they each have?
How about this question? Can we solve it the old-fashioned way?
In what way? Painting? Make up the number? Please upload your answers.
It would be much easier if we used the equation method.
Please see:
Suppose everyone has x sheep.
5x+9x=420
14x =420
x =30
The power of equations is really great. X is like a little magician. We must study.
Make good use of this magician to solve more math problems.