125×35 is equal to 4,375.
I would set up the math like this. I would take 5 times 5, which is 25. I would put the 5 first and carry the two to add on to the next number. So 5 times 2 is 10, plus the 2 from the previous one would be 12. You would take 5 times 1, which is 5, but add the one which came from the 12, so it would be 6. For 35, you would pit a 0 directly under the first 5, as I did in the picture and you would basically do 3×5,3×2+1 fro. the fifteen, etc.