2. CROSS MULTIPLICATION

3. Start from r.h.s, if there is any carry in any part,it is to be added to next part. A B C D C*A (D.A + B*C) B*D

4. 1 2 4 3 1*4 1*3+4*2 2*3 4 11 6 4+1 1 6 5 1 6

5. 5 6 1 4 1*5 1*6+5*4 6*4 5 6+20 24 5 26 24 5 26+2 4 5+2 8 4 7 8 4

6. MULTIPLICATION OF NUMBERS WHERE DIFFRENCE IS even :

7. We know : (a+1) * (a-1) = a * a – 1 24 * 26 Find the midpoint of 24 and 26 i.e. 25 Now square of 25 = 625 Final answer = 625-1 = 624 =24*26

8. 49 * 51 50 * 50 = 2500 2500-1 = 2499 ----------------------------------------------- 84*86 85*85=8*9 25=7225 7225-1=7224

9. We know (a-2)*(a+2) = a*a – 4 21 * 25 Find the Mid point of 21 and 25 i.e. 23 Now square of mid point : 23*23 = 529 Final answer = 529 – 4 = 525

10. 47 * 43 Mid point – 45 45*45=4*5|5*5=2025 2025-4= 2021 ------------------------------------------- 88*84 Mid point – 86 86 * 86 = 7396-4= 7392