GRADE 3 · ALBERTAOUTCOME AB-G3-3N3
L1 · Strategies: multiplying in parts; compensation; partitioning the dividend
Learning goal
“I can multiply by breaking one number into parts, use compensation to turn a hard fact into a friendly one, and divide by partitioning the dividend into easy parts.”
Multiply in parts — break one factor into parts, multiply each part, then add: 6 × 14 is 6 × 10 and 6 × 4.
Compensation — change a number to a friendly one, multiply, then fix the change: 9 × 6 is 10 × 6, then take away the extra 6.
Partition the dividend — split the number being divided into easy parts: 84 ÷ 4 is 80 ÷ 4 and 4 ÷ 4.
Worked example
6 × 14. Step 1 (break 14 into parts): 14 = 10 + 4. Step 2 (multiply each part by 6): 6 × 10 = 60; 6 × 4 = 24. Step 3 (add the parts): 60 + 24 = 84. So 6 × 14 = 84. Picture it: an array with 6 rows and 14 columns. A line after the 10th column makes two small arrays - one is 6 × 10, the other is 6 × 4. No dots were lost. The parts add back to the whole array.
Check yourself — explain it
Why do we add 60 and 24?
Paired problem — example still visible
7 × 12 -> 7 × 10 = 70; 7 × 2 = 14; 70 + 14 = 84
Faded completion — last step is yours
"5 × 16: 5 × 10 = 50; 5 × 6 = ___; total = ___." -> 30; 80
Ready to practise?
10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.