Mixed operationsUp to 100
All four operations worksheets
The last step in fact fluency is a page that gives no clue about which operation is coming next. These free printable worksheets put addition, subtraction, multiplication and division side by side, so every single question opens with a decision.
If they get stuck

The answer key prints on a separate page.
What's on this sheet
Practicing one operation at a time is how each one is learned, and it hides something: a child can finish twenty questions without ever reading a sign. A mixed page takes that shortcut away. It is usually the first sheet on which a confident pupil visibly slows down, and the slowing down is exactly what you are looking for.
Why this sheet works
The addition and subtraction questions run to 100 and the multiplication and division stay inside the standard tables, so nothing here is harder than the sheets it is assembled from. What is harder is the switching, and switching is a separate skill that end-of-year checks test directly.
How this one works
One question from a sheet like this one, worked a step at a time — with a sentence saying what just happened and why.
All four operations, step by step