Update README.md

This dataset comprises two columns: `Problem Description` and `Solution`. Each row in the `Problem Description`column presents a linear equation in the form of:
```
ay + b = dy + c
```
Correspondingly, the `Solution` column provides a step-by-step method to solve these linear equations.

README.md

@@ -2,6 +2,7 @@
 license: apache-2.0
 task_categories:
 - text-generation
+- question-answering
 language:
 - en
 size_categories: