Learn Turkish: Bu fark çok küçük. - This difference is very small.

In Turkish, there is no direct equivalent for the "to be" verb (am, is, or are) when making simple statements about what something is. For the "it" form (third person singular), you just put the subject and the adjective together. So, Bu fark çok küçük literally translates to "This difference very small," but naturally means "This difference is very small."

I learned that çok means "a lot" or "much". Why is it translated as "very" here?

Çok is a very useful and flexible word! When you use it before a noun, it means "much," "many," or "a lot." But when you place it directly before an adjective like küçük (small), it acts as an intensifier and changes its meaning to "very."

If I wanted to say "these differences", would the word bu change to a plural form?

No, it wouldn't change! When used as an adjective right before a noun, demonstrative words like bu (this), şu (that), and o (that over there) never take a plural ending in Turkish. You would simply pluralize the noun to get bu farklar (these differences). Saying bunlar farklar would be incorrect.