Cross Sum Volume One

Every puzzle is unique, and so is its level of challenge. To help you gauge the complexity of each, we use a star rating system.
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For those who are just getting started - gentle and welcoming. Remember the order of operations:
1. Multiplication and division from left to right
2. Addition and subtraction from left to right.

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Intermediate level - For the seasoned mathematician who is ready for a robust challenge. Get ready for fractions.
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Where things get a tad more intricate - the big leagues! Puzzles that demand attention and skill. We've added negative numbers to these.
No matter the level of your math skills, this volume promises an atmosphere of mental stimulation and challenge. Try not to peek, but if you must, all solutions start after puzzle #180.