Combined Grade 2/3? Math at the start of the year? September and October are a perfect time to teach number sense. This unit offers lessons and assessments that will help students build a sense of equality (algebra), concepts in number, and operational sense at the Grade 2 and 3 levels. Based on Ontario Curriculum Expectations, aligned with the Common Core. The unit is likely to last between 4 - 7 weeks, takings into account students' needs and scheduling.