Ready to help you, when you have problems on mathematics home work. Im teacher at senior high school n master degree at yogyakarta state university. Grades K-2: Addition and subtraction Grades 3-5: Multiplication and division of whole numbers and fractions Grade 6: Ratios and proportional relationships, and early algebraic expressions and equations Grade 7: Ratios and proportional relationships, and arithmetic of rational numbers Grade 8: Linear algebra and linear functions.