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
Har column ka digit-sum agar 10 se zyada ho, to carry agle column mein already accounted ho jaata hai jab tum "attach 0/00" karte ho aur end mein combine karte ho — bas final addition mein dhyan se carry lagana, step-by-step carry mat karna.
⚡ QUICK RECALL
Yeh column-addition ka mental-math version hai — sabse right column se ulta shuru karke place-values ko group karo, phir sabko jod do.