These are a useful couple of pages for children entering Year 3 next term. Counting on and back will still be important in year 3, using up to three digit numbers. Grouping into tens or fives and using tally charts are both effective ways of counting larger numbers.
Children seldom get a chance to count a larger number of objects – somewhere between 30 and 60. By seeing and counting this many they become more able to estimate larger numbers and be able to give rough approximations rather than wild guesses.
Try similar exercises with heaps of coins, counters etc, dividing them up into fives or tens. A really good idea is to collect change (pennies etc) and guess how much of any one coin there is.