Adding and Subtracting within 100
In this unit students • add and subtract multiples of ten; • add and subtract a two-digit number and a one-digit number, or a two-digit number and multiple of ten; • make adding and subtracting strategies explicit; • write addition and subtraction equations.
In this unit students use their understanding of addition and subtraction contexts and place value to add and subtract within 100. They add two-digit numbers with one-digit numbers, and two-digit numbers with multiples of ten. They subtract multiples of ten using pictorial representations and number lines. They continue to develop strategies for adding and subtracting based on place value, the properties of operations, and the relationship between addition and subtraction. They get further practice with writing addition and subtraction equations, as well as more practice towards fluency with adding and subtracting within 10. Students organize, represent, and interpret data and answer addition and subtraction questions related to the data as way of providing further practice with adding and subtracting within 100.