Mathematics help for Silvia, preparing for the school-leaving exam

My younger sister, Silvia, is 14 and in the final year of school. Silvia loves school but mathematics has been a struggle since the school was closed during the strikes. The school-leaving exam is in December. We can't afford a private tutor, and the school's free sessions are full. We're looking for a volunteer who could spend one or two hours a week, in person in Coyoacán or online, for about twelve weeks. Silvia is polite, hardworking and eager. We have a quiet space and a laptop for online sessions. I'll always be at home for in-person sessions. If you're a teacher, student or professional who feels comfortable in mathematics, you could change the course of Silvia's year. Even a small gift gets used right away and I'll thank you myself.