it doesn't take a rocket scientist to (do something)

it is easy to understand something.

It doesn't take a rocket scientist to understand that fewer and fewer schools can afford to maintain competitive athletic programs.

Usage notes: sometimes used in the form it's not rocket science:

A five year old could put this puzzle together — it's not rocket science.

• curtain comes down on something
• curtain falls
• curtain falls on
• curtain falls on something
• cushion the blow
• cut above
• cut above someone
• cut above something
• cut across
• cut across something
• cut a deal
• cut a figure
• cut a fine figure
• cut a long story short
• cut-and-dried
• cut and run
• cut and thrust of
• cut and thrust of something
• cut an ... figure
• cut an figure
• cut an interesting figure
• cut an [interesting/ridiculous/unusual etc.] figure
• cut an ridiculous figure
• cut an unusual figure
• cut a rug