oppia: [BUG]: Feedback to learner's incorrect input is confusing

Describe the bug

Learner might not be able to understand the exact input that is wrong with their answer based on the feedback that is being given on the portal.

URL of the page where the issue is observed.

https://www.oppia.org/create/rwN3YPG9XWZa?story_url_fragment=a-day-at-the-amusement-park&topic_url_fragment=exprs-and-eqns&classroom_url_fragment=math&node_id=node_9#/preview/P1 - unknown

Steps To Reproduce

Type in 30 - 12 = 18 in the math input text box. An error message will pop up that 'It looks like you have entered an equation/inequality. Please enter an expression instead. ’

Expected Behavior

I expected the feedback to be something learner can easily understand. I suggest changing it to “It looks like you have entered an equals sign which turns your answer into an equation. Please remove the equals sign to make your answer an expression”

Screenshots/Videos

What device are you using?

Desktop, Mobile

Operating System

Windows, Android

What browsers are you seeing the problem on?

Chrome

Browser version

Version 111.0.5563.146 (Official Build) (64-bit)

Additional context

No response

Tips for developers

Before tackling the bug, please use git bisect (see https://git-scm.com/docs/git-bisect) to investigate which PR caused it (you only need to go back as far as commit https://github.com/oppia/oppia/commits/9a334e9). If you find the PR, leave a comment on this issue pointing to it, or just say that it happened before commit 9a334e9 if you could reproduce it there. This will help us fix the issue by reverting the faulty PR.

Also, if this is your first issue, please make sure to follow https://github.com/oppia/oppia/wiki/Contributing-code-to-Oppia#choosing-a-good-first-issue and https://github.com/oppia/oppia/wiki/Contributing-code-to-Oppia#setting-things-up before claiming it. Thanks!