GRADE 1 · ALBERTAOUTCOME AB-G1-1N2
L2 · Part-part-whole: two parts make a whole
Learning goal
“I can break a number into two parts, and I can put two parts together to make the whole.”
Whole — the full amount, all of it together.
Part — one piece of the whole. A whole can break into two parts.
Part-part-whole mat — a mat with one big space for the whole and two spaces for the parts.
Break apart — split a whole into parts. The parts still add up to the whole.
Worked example
A mat has 8 counters in all. 5 are red and the rest are blue. How many are blue? Step 1: The whole is 8. One part is 5. Step 2: The other part must make the whole: 5 and what makes 8? Step 3: 5 and 3 make 8. So 3 counters are blue. Model: the part-part-whole mat described in words - whole bar on top (8), two part boxes below (5 and 3).
Check yourself — explain it
The whole is 8 and one part is 5. The other part is...
Paired problem — example still visible
A mat has 7 counters in all: 4 on one side, the rest on the other side. How many on the other side? -> 3
Faded completion — last step is yours
"The whole is 9. One part is 6. The other part is ___." -> 3
Ready to practise?
8 scored questions with a 3-rung hint ladder. Mastery needs 7/8 plus both gate questions.