Contact us

Questions? We read every message.

Not sure which book fits, need help with an order, or spotted something that isn't right? Send it over — a real person at Muscle Math Mania reads it.

Send us a message

Please don't include card numbers or passwords — we will never ask for them.

For a possible mistake, include the book, page and problem number.

This form is for adults. We use your address only to reply — see our privacy policy.

Digital (PDF) orders

Reply directly to your Lemon Squeezy receipt email. That thread is tied to your order, so it's the fastest and most secure way to get a download re-sent or a payment question answered.

Paperback orders

Paperbacks are printed and shipped by Amazon. For delivery, returns or refunds, use Your Orders in your Amazon account — Amazon handles those directly.

Found a mistake?

Tell us the book, page and problem number. We check every report against the source and fix it in the next printing.

Schools & groups

The PDF licence covers one household. For a classroom, tutoring group or co-op, pick “Schools, co-ops & bulk orders” in the form and tell us what you need.

Before you write

The quick answers.

Which book should my child start with?

Go by what they can do, not their grade. Download the free sample for the book you think fits — if the first lesson feels easy, move up one; if the warm-up is a struggle, step down one. Free samples are here.

My PDF download link expired.

Reply to your Lemon Squeezy receipt email and ask for it to be re-sent — include nothing but your order number.

Can I use the PDF with my class?

The standard licence is for one household. Send us a message with the topic “Schools, co-ops & bulk orders” and tell us about your group.