Missing Number Equations

Oh no! A thief has stolen a number and now there is a missing number in this equation! Can you help me fix it?

The equation is 

54 – ?  = 49

What number did the thief steal?

How can you work it out? 

Can you explain your thinking? Remind students of fact families.

Enabling: Subtract from 10 – Using friends of 10, can you fill in the missing numbers?

10 – ? = 6

10 – ? = 2

Extending: Use a 3 or 4 digit number. How did you get there? Can you explain your reasoning?