Question

A. Mr. Wang writes a number on the whiteboard. Sally adds 5.5 to Mr. Wang's number to find a new number. Then, Tom subtracts 4.5 from Sally's number to find a new number. Then, Tarik subtracts 1.5 from Tom's number to find a new number. Finally, Puja adds 9.25 to Tarik's number to find the final number, which is 1.75.

Answer 1

Let's break down the problem step by step to find Mr. Wang's original number.

Let \( x \) be the number Mr. Wang writes on the whiteboard.

1. Sally adds 5.5 to this number:
\[
x + 5.5
\]

2. Tom subtracts 4.5 from Sally's number:
\[
(x + 5.5) - 4.5 = x + 1
\]

3. Tarik subtracts 1.5 from Tom's number:
\[
(x + 1) - 1.5 = x - 0.5
\]

4. Finally, Puja adds 9.25 to Tarik's number:
\[
(x - 0.5) + 9.25 = x + 8.75
\]

According to the problem, this final number equals 1.75:
\[
x + 8.75 = 1.75
\]

To find \( x \), we can solve for it:
\[
x = 1.75 - 8.75
\]
\[
x = -7
\]

Thus, Mr. Wang's original number is \( \boxed{-7} \).