Rational arrays make 24 There are four rational numbers: 3,4, - 6,10. Add, subtract, multiply and divide these four numbers (each number is used only once) so that the result is 24. Write three kinds of essentially different formulas

Rational arrays make 24 There are four rational numbers: 3,4, - 6,10. Add, subtract, multiply and divide these four numbers (each number is used only once) so that the result is 24. Write three kinds of essentially different formulas

There are four
3×[10+4+(-6)]=24
3×(10-4)-(-6)=24
10-4-3×(-6)=24
4-(-6)×10÷3=24

+Must a be a positive rational number? - must a be a negative rational number? Why?

+A is not necessarily a positive rational number
① If a is negative, then a is negative
② If a is irrational, then + A is irrational, not rational
-A is not necessarily a negative rational number
① If a is negative, then - A is positive
② If a is irrational, then - A is irrational, not rational

As for rational numbers, why can only integers plus fractions be rational numbers? Must the combination of the two be rational numbers,
How do the two form rational numbers, and about irrational numbers, whether numbers whose root sign is not equal to 0 are irrational numbers, why do numbers have root signs, and what kind of role does the root logarithm play

At that time, when I was studying, the teacher said that rational numbers are the general name of integers and fractions, and all rational numbers can be converted into fractions. Irrational numbers are infinite non circulating decimals. That is to say, they can't open the root sign, and of course they can't be converted into fractions