Interesting mathematics = 2000 when they represent what number, the formula holds

Interesting mathematics = 2000 when they represent what number, the formula holds

The title should be like this
learn
mathematics
Taste mathematics
+Interesting mathematics
————————
=2 0 0 0
Learning = 5
Number = 6
Taste = 4
Fun = 1

Interesting math problem:
The first day, a and B to eat a total of 25 yuan, two half out, by B advance
The next day, a and B go to dinner. A spends 11 yuan for dinner, 1.5 yuan for coke, and 9 yuan for B. A checks out the bill. As a result, a finds that he doesn't have enough money to pay for today's meal. After a pays the boss 21 yuan, B gives the boss 1 yuan and the boss gives him the change
How much does a owe B?

Let's look at it by the chart. A pay a pay B pay a owe / be owed B the first day 0 - 12.5 - 25 - 12.5

Interesting plus interesting plus interesting number in addition to interesting mathematics, what are the numbers equal to 7531 addends

Interesting + interesting + interesting number + interesting mathematics = 7531 if interest = x, taste = y, number = Z, learning = a, then: XXX + YYY + ZZ + a = 7531x, the maximum is 6, that is: 6666, then: 7531-6666 = 865y, the maximum is 7, that is: 777, then: 865-777 = 88z, the maximum is 8, that is: 88, then: a = 0, so: interest = 6, taste = 7, number = 8, learning = 0, that is: 0 + 88

Fun + fun + fun number + fun math = 7531
Please explain the solution

Fun = 6
Taste = 7
Number = 8
Learning = 0
6+67+678+6780＝7531