| title | ISBN-13 | year of publication |
|---|---|---|
| Cracking Basics - Addition Ages 4+ | 978-1-5220-4531-1 | 2017 |
| Cracking Basics - Division Ages 7+ | 978-1-9734-7055-7 | 2017 |
| Cracking Basics - Multiplication Ages 6+ | 978-1-5220-9302-2 | 2017 |
| Cracking Basics - Subtraction Ages 5+ | 978-1-5220-7189-1 | 2017 |
| Cracking Basics - Year 3 Fractions Age 7 to 8 | 978-1-7933-6282-7 | 2019 |
| IVXLCDM Cracking Roman Numerals Ages 9+ | 978-1-9804-1115-4 | 2018 |
R. B · R. Bell · R. S. · Robert B. · Robert Bell · Robert S. · S. B · S. Bell