Whilst this worksheet appears to be very simple it is surprising how many children get into a bit of a muddle with such activities. A table is shown with a rule for completing it, such as ‘Add 34’. All that has to be done is complete the missing cells of the table following the rule. If the second (OUT) number has to be found then it is a straightforward matter of using the rule. If the first (IN) number has to be found then the rule has to be reversed: it becomes clear as you do the worksheet!
The fourth question does not give the rule, but it can be found by seeing what has happened from the IN number (40) to the OUT number (25); in this case it is subtract 15.
This is well suited to Year 5 children who are good at adding and subtracting two digit numbers mentally. It can be found in our Year 5, Calculating category.
- © 2009 Maths Blog