The differences between Edexcel International GCSE (9–1) Mathematics A and B:
https://qualifications.pearson.com/content/dam/pdf/International%20GCSE/General/pearson-edexcel-international-gcse-9-1-maths-guide.pdf
Specification for Pearson Edexcel International GCSE Mathematics (A):
https://qualifications.pearson.com/en/qualifications/edexcel-international-gcses/international-gcse-mathematics-a-2016.html