NCERT books are most favourable referances for government exam preparation. Here we are coming with book name as Mathematics of class 6
There are many situations provided in the book where children will be verifying principles or patterns and would also be trying to find out exceptions to these. So, while on the one hand children would be expected to observe patterns and make generalisations, they would also be required to identify and find exceptions to the generalisations, extend patterns to new situations and check their validity. This is an essential part of the ideas of Mathematics learning and therefore, if you can find other places where such exercises can be created for students, it would be useful. They must have many opportunities to solve problems themselves and reflect on the solutions obtained. It is hoped that you would give children the opportunity to provide logical arguments for different ideas and expect them to follow logical arguments and find loopholes in the arguments presented. This is necessary for them to develop the ability to understand what it means to prove something and also become confident about the underlying concepts.