You give them an answer they can agree on, and they become more mature. The next time this happens, they will act more grown up. That's all prayer is. God gives free will, and you allow God to intervene, making you a little more like God. As far as seeing the future from the beginning, it also says that God is in the past, present and future.
Time is simultaneous.
However, I believe the future is different in that it is always changing, depending on what we choose to do. In A Christmas Carol , Scrooge sees the future, but by changing the present, he also changes the future. There is little mention of God being omnipotent in the Bible. This concept emerged later when certain European rulers wanted to embellish their authority by promoting the concept of God controlling everything, and thus if I'm in charge it must be because God wants it that way. The Bible has many examples of God trying things that don't work out that well, implying that God is not all powerful or all-knowing.