345*145

O.K....... Your problem is that, you're getting difficulties in multiplication of such 3 or 4 digit numbers, Right......

So, I've a solution for it........O.K........So, watch carefully and Understand what i am trying to say, Huh......

For Instance, Let Take your Question is :- 345 x 145 so, firstly, write it as

      3       4       5

x    1       4       5   Huh,,,,so, it doesn't matter whether , you write the bigger no. in the first row or smaller no., your answer will be same......so, let take it as :

      1       4       5

x    3       4       5      O.K........now, straight multiply the last column element and start writing the answer from right, we know that 5 x 5 = 25, so take 2 as carry and write 5 at the right of your answer,for ex......yyyy5 and 2 as carry......

Now, cross multiply the last second column elements and add both of it with the carry......so, 4 x 5 = 20 and 5 x 4 = 20 and carry is 2, so, by adding we get 20 + 20 + 2 = 42 so, write two at the left of your answer and now, take 4 as carry....Huh, so, your ans. looks like yyy25.....O.K.

Now cross multiply first and third column and straight multiplt second column and add it with the carry.....Huh......so, it will be 1 x 5 = 5 and 3 x 5 = 15 and 4 x 4 = 16 and carry is 4 so, it will be 5 + 15 + 16 + 4 =     40.....now, take 4 as carry and your ans, looks like yy025...... O.K.

now, cross multiply first column with second and add carry 4, so, 1 x 4 = 4 and 4 x 3 = 12 and carry is 4 so, we get 4 + 12 + 4 = 20.....now take 2 as carry and the ans. looks like   y0025

O.K. so, now the last step straight multiply first column and add carry 2 so, we get 1 x 3 = 3 and carry is 2....now add it 3 + 2 = 5.....so, the exact ans. will be 50025....that's all seems to be lengthy  but it isn't and try to do all the calculation in mind and write ans. directly....the calculations are not so big...so. you'n do them in your mind.....try it again and again even if the digits are not similar like 2990 x 548 so put zero in front of the less digit no. and do the same calculation.... like 2990 x 0548 O.K. so that's it......good Bye, Hopes you'll understand what I'm trying to say....... :)