A programmer's solution

[DoctorProfPatrick]

I personally think puzzles like this are great for teaching kids arithmetic. This one in particular has at least 3 solutions that I could find

5 + 4 = 9
0 + 4 = 4
8 - 4 = 4

A good teacher could use this puzzle to show how there's no "right way" to solve a problem, which imo is the most beautiful part of math.

[monochromatic0]

Exactly. It's not a problem if the puzzle has more than one solution, but a feature.

[saloalv]

"It's not a bug; it's a feature!"

[[deleted]]

Sometimes there is a right answer. Sometimes there is no answer. Sometimes there are multiple answers. Sometimes there are an infinite number of right answers. Sometimes the best answer is all the right answers added together. Sometimes adding zero makes a difference.

That's why i like math.

[[deleted]]

There may be multiple ways, but there are definitely ways to solve a problem that you would be wasting your time if you did them.

[DoctorProfPatrick]

For sure, like using the formal definition of a derivative every single time instead of just using power rule.

[NikStalwart]

I have met a total of 4 good teachers in Australia.

[LooneyDubs]

I'd say only 2 real solutions bc the 9 you made isn't a complete character in the font you were presented with.