Bdtyk

I'm looking to create an appropriate title for a science fair project and I'm questioning which of these three words would be most grammatically appropriate and correct: "optimal","optimum" or "ideal". "Creating the Optimal Computer for Literacy at Half the Cost", "Creating the Optimum Computer for Literacy at Half the Cost", or "Creating the Ideal Computer for Literacy at Half the Cost"? Any suggestions are appreciated.

Short answer: all three are fine.

As for the first two options, let's see what Merriam Webster has to say:

Optimal and optimum both mean “best possible” or “most favorable.” Optimal is used solely as an adjective, as in “optimal method of completion, while optimum functions as both a noun, as in something “being at its optimum,” and an adjective, “optimum method,” although this is less common.

https://www.merriam-webster.com/words-at-play/optimum-vs-optimal

As this article explains, English writers borrowed the noun optimum from Latin in the 19th century. Within a short time, optimum began to be used as an adjective and almost simultaneously a new word, optimal, appeared, which was also used as an adjectival form of optimum. Today, both words are used as adjectives, but optimal appears to be used somewhat more frequently.

As for ideal, in this case, its meaning is virtually identical to optimal/optimum.

ideal

Adjective

1 Satisfying one's conception of what is perfect; most suitable.

https://en.oxforddictionaries.com/definition/ideal

I've seen optimal/optimum applied more frequently to cases where the results can be objectively measured, for example "An algorithm optimized for speed."

Ideal is the better choice if the criteria is less objective and more open to human opinion, belief, or even personal preference. For example, "The ideal candidate for Governor."

Though I don't really know what you mean by "Computer for Literacy", I'd suspect you want 'ideal' or one of its close synonyms like 'preferable' or 'most suitable'/'best suited'.