Error Rectification in accounting - Explanation with examples

Rectify: (1) Cash sales ₹12,000 recorded as ₹1,200; (2) Goods sold to Raju ₹5,000 posted to Ramu; (3) Purchase book overcast by ₹2,000; (4) Cash paid to supplier ₹3,000 posted twice; (5) Discount allowed ₹700 posted to Discount Received. Pass the entry for item 1.