Question 1:
<h3>Answer: The number does <u>not</u> change</h3>
Removing the zero from 0.76 leads to .76 which is the same as before. Both lead to
in scientific notation.
Personally I prefer the zero up front to make the decimal point stand out easier. Of course it's just a preference, so its up to you to decide which you prefer.
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Question 2:
<h3>Answer: Yes the number changes</h3>
Taking the zero out of 10.25 leads to 1.25 which is definitely a different number (and smaller). Therefore, this zero is a significant digit compared to before.
We have been given that Sterre charges $35 to file tax returns, but files for free if she only needs the easiest form. Also, she donates $2 to clean water projects per tax return she files.
Further we know that Sterre charged $7,245 and made a donation of $1,242 this year for the tax returns she filed.
Let x be the number of free income tax returns and y be the number of $35 income tax returns.
Therefore, we can set up:

Since she donates $2 for each return that she files, therefore, we can set up:

Therefore,
Sterre filed 414 tax returns for free and filed 207 tax returns for $35.