How many integers are there on the number line between $2\sqrt{10}$ and $10\sqrt{2}$?
+1005 2sqrt(10) goes just above 6, so we start at 7. 10sqrt(2) is just above 14, so we use 14.
7-14 goes to (7-6) - (14-6) and 1 - 8. 8 ints.
If you don't understand anything feel free to ask.
