Principles of operations apply to algebra; continuous linear relationships; similar shapes
Below is how the official curriculum organizes it. Each strand will get full lessons like the ones in Grade 1 Mathematics.
Operations with rational numbers; exponents and exponent laws with whole-number exponents
Operations with polynomials of degree 2 or less
Two-variable linear relations (graphing, interpolation, extrapolation); multi-step one-variable linear equations
Spatial proportional reasoning (similar shapes, scale)
Statistics in society: validity, reliability and representation of data
Simple budgets and transactions