Fact families are soo important in helping children to understand inverses and relationships between calculations. But it's so interesting to see that some children don't really understand fact families because they didn't really get how useful they were in the first place! Children really need to revisit concepts frequently and see the importance of what they are learning and how they are useful.
Once a children really understands the relationships between adding and subtracting and multiplication and division then it takes their learning on to a different level.
Start with very basic calculations and get the children to make a fact family...
6+4=10
4+6=10
10-4=6
10-6=4
Once they understand this they then need to apply this knowledge....
10- ?=6
what can help us with this problem?
what else do we know about this calculation?
writing the fact family helps
10-?=6
10-6=?
6+?=10
?+6=10
It's at this point that the children can look through the calculations and see which number sentence is easiest to solve....