VEDIC MATHS :Multiplying by thirteen
Put the tens digit on the left, the unit number on the right, add them up together in the middle. Then add double the number to the previous result. For example: 13 × 22 Step 1: (2 × 100) + 2 + [(2 + 2) × 10] = 242. Step 2: 22 × 2 = 44. Answer: 242 + 44 = 286. If the two digits sum to more than ten, then you carry the one to add it to the number on the left and continue. For example: 13 × 65 Step 1: (6 × 100) + 5 + [(6 + 5) × 10] = 715. Step 2: 65 × 2 = 130. Answer: 715 + 130 = 845.