Use when: many numbers (5+) are added together in one go — group by place value instead of adding sequentially
Example: 67+68+35+43+65+55
Step 1: Add all tens-place digits: 6+6+3+4+6+5 = 30
Step 2: Attach a 0: 300
Step 3: Add all units-place digits: 7+8+5+3+5+5 = 33
Step 4: Combine: 300+33 = 333
Example: 56+48+78+567+983 (with hundreds place)
Step 1: Add hundreds-place digits: 5+9 = 14 → attach 00 → 1400
Step 2: Add tens-place digits: 5+4+7+6+8 = 30 → attach 0 → 300
Step 3: Add units-place digits: 6+8+8+7+3 = 32
Step 4: Combine: 1400+300+32 = 1732
⚠ EXAM TRAP
If a column's digit sum exceeds 10, the carry into the next column is already accounted for when you attach 0 or 00 and combine at the end. Apply the carry carefully in the final addition rather than carrying at every step.
⚡ QUICK RECALL
This is the mental-maths version of column addition: begin with the rightmost column, group the place values in reverse order, and then add them all.