1, normalization problem
2. The problem of induction
3. Sum and difference problem
4, and the times.
5, the problem of differential time
Step 6 double the problem
7. Meeting issues
8. Catch up with the problem
9. Planting trees
10, age problem
1 1, navigation problem
12, train problem
13, clock problem
14, profit and loss problem
15, engineering problems
16, positive-negative ratio problem
17, distributed in proportion
18, percentage problem
19, the problem of "cattle eating grass"
20. The cage problem of chickens and rabbits
2 1, square matrix problem
22, commodity profit problem
23, deposit interest rate problem
24, solution concentration problem
25, composition number problem
26. Magic Square Problem
27, pigeonhole principle problem.
28. Equality in the Convention.
29. The most important issue
30, column equation problem