Finding difference between whole numbers

New Zealand Curriculum: Level 2

Learning Progression Frameworks: Additive thinking, Signpost 4 to Signpost 5

Target students

These activities are intended for students who understand addition to be the joining of sets and subtraction to be the removal of objects from a set. Difference problems require the student to compare the numbers of objects in two different sets and can be solved using either addition or subtraction. Comparison situations are structurally distinct from the part-whole situations students commonly encounter in early instruction about addition and subtraction.

Target students should have already developed a degree of part-whole understanding in addition and subtraction contexts (joining and separating). They should have some number facts to call on, particularly number bonds to ten. Understanding of two-digit place value, including the structure of ‘teen’ and ‘ty’ numbers is supportive to many to the activities described in this intervention.

Allow access to pencil and paper but not to a calculator. You need a set of ice block sticks, bundled in tens and hundreds, masking cards (half A4 size), note paper to record numbers and a marker pen. (show diagnostic questions)

Teaching activities