Physical copies can be hard to find outside of major Bangladeshi bookstores.
Many engineering universities in South Asia digitize out-of-copyright technical series. Search on institutional websites using the query: site:edu.bd "Saimum Series 64" pdf (replace with your country's domain, such as .in or .pk). saimum series 64 pdf
PDFs allow users to use Ctrl+F to find specific topics or solution sets. If a student needs to find every instance of "Age related math" in Series 64, a PDF does this in seconds. Physical copies can be hard to find outside