The creation of the universe took six days, according to the literal interpretation of the Book of Genesis. Creationists accept this as fact as they feel that the words of the Bible are those of God, who inspired humans to write them thousands of years ago. So, because the word "day" is printed on the page, it took six twenty four hour blocks of time to make the universe. There is a fundamental problem with this.
Let us consider the present English translation of the Bible. It originated with the Old Testament, which was written more than 2500 years ago in Hebrew. Aramaic was the common language at the time of Christ and certain of the later books of the Old Testament, or Torah, were written. Demotic Greek versions sprang at this time (Koine). The Latin version soon followed a few centuries later, penned by St. Jerome. Several English versions came about, with some Middle English (Chaucerian) metrical versions starting around 1250. The Wycliffe version appeared in 1390, followed by several Reformation translations of original documents, such as Tyndale's in 1526. King James I commissioned the Authorised Version (known also as the King James Version), and many churches now use modern English equivalents. Keep in mind the the latter few are different versions in the same language (English). I have translated many works between English, French, and Latin and I find that it is close to impossible to create a 100% accurate translation. This is because different languages have different idiomatic nuances. There is an old cliché "it loses something in the translation."
If God guided the hand of the humans who first put His version into print (for which there is no proof), did he help correct any translation errors? In fact Hebrew requires the context of the sentence to determine the exact meaning of many words. English has some examples: consider the word "set"what does it mean? It could mean many things depending on the context. Television set. Settle down. A set of tennis. The cement has set. In the case of Hebrew and Greek context is even more important. Did the ancient Hebrew word for day mean "extent of time" or "twenty four hours"? This is a crucial question if you are literally interpreting the Bible.