In conclusion, while I couldn't find a direct link to the Casco Mathematics Tutor 2A PDF, the series appears to be a useful resource for students in Singapore. If you're looking for alternative resources, there are many online and offline options available that can provide similar support for mathematics students.
"The link," Silas said, gesturing to it. "This is the key. It is the digital preservation of the text. It is the exact same exercises, the same diagrams, the same logic. But it is accessible to you right now, in this moment, without waiting for a inter-library loan that might never come." casco mathematics tutor 2a pdf link