7 - 8 year olds

1. I love writing numbers. Today I have started in in number 41 and written all these following it:

41424344454647484950 ... and the following ones..

Having such a long number, when I have 10 I dont write it.

What is the addition of the first ten numbers that I erased?

2--- Yesterday I did the same but I started with the number 31, but instead of deleting of the 10th one I deleted the 5th..

What is the addition of the first ten numbers that I erased?