GRADE 2 · ALBERTAOUTCOME AB-MAT2-N2
L4 · Adding two-digit numbers
Learning goal
“I can add two-digit numbers with partial sums: add the tens, add the ones, then join the parts - and when the ones make more than ten, I make a new ten.”
Tens — the groups of ten inside a number. 46 has 4 tens.
Ones — the single ones inside a number. 46 has 6 ones.
Partial sums — adding part by part: first the tens part, then the ones part, then joining the parts.
Two-digit number — a number built from tens and ones, like 46.
Worked example
Add 34 + 25. Step 1 - TENS PART: 34 is 3 tens and 4 ones; 25 is 2 tens and 5 ones. 30 + 20 = 50. Step 2 - ONES PART: 4 + 5 = 9. Step 3 - JOIN: 50 + 9 = 59. So 34 + 25 = 59. Add the parts, then join the parts.
Check yourself — explain it
Why do we add the tens first in 34 + 25?
Paired problem — example still visible
42 + 36: tens part, ones part, join. -> 70 + 8 = 78
Faded completion — last step is yours
53 + 24: tens 50 + 20 = 70; ones 3 + 4 = 7; sum = ___ -> 77
Ready to practise?
10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.