Let's call the mystery number ' Q '
Five more than the number . . . (Q + 5)
The question says that's 3, so . . . Q + 5 = 3
Subtract 5 from each side . . . Q = -2
I'm not sure if you use "x" as your variable, so:
# + 5 = 3 or x + 5 = 3
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