To complement the Addition Strategy Posters I use in class, I've also made Subtraction Strategy Posters. They are in the same format, but use a different background, as well as having 'Subtraction' in red at the bottom of each poster, to help kids differentiate between the addition and subtraction strategies when they are using them as a reference.
These are great mental math supports that will help the children in your class as they use and explain their use of different mental maths strategies during Number Talks.
This file has 5 posters illustrating subtraction strategies that your class may use when subtracting within 100, with an additional 2 posters illustrating different ways children may use the 'Break Apart by Place Value' strategy.
If the strategy illustrations in these posters aren't quite right for your class, there are also 2 more FREE Strategy posters files available - one of the files has the same posters, only the strategies are illustrated with numbers in the 100s, while the other file has 3 posters, illustrating 3 simple strategies that children may use during Number Talks when they are subtracting within 10.
Each strategy (just like my addition posters) has a fun 'strategy name' that I find helps the kids remember and use the individual strategies.
Hope you find these helpful!