SG chevron_right Secondary 1 chevron_right Number and Algebra

Help I do not know how to do the working for this question.

SG chevron_right Primary 4 chevron_right Number and Algebra

Mei Mei , Gina and Sara had 825 sticks altogether.Mei Mei had twice as many stickers as Gina.Gina had 15 stickers more than Sara.How many stickers did Sara have?

SG chevron_right Primary 5 chevron_right Number and Algebra

SG chevron_right Primary 5 chevron_right Number and Algebra

SG chevron_right Secondary 5 chevron_right Add Math: Algebra