This is the second page which looks in detail at a 1-100 number square and is excellent practice at understanding place value as well as counting.
A small section of the whole number square, just 4 by 3 is taken and most of the numbers removed. The skill is in replacing the missing numbers.
This can be done in a variety of ways. Probably the easiest way is to work across as each number is one more than the number to the left. One of the more interesting ways is to work down as each number is 10 more than the number above.
Missing numbers on a number square (pg 2)
Many more KS1 resources can be found at urbrainy.com