Logic Masters Deutschland e.V.

This puzzle has been constructed as a practice puzzle for this years WSPC.

Rules (partly taken from the WPC):
Standard Cross Sums: Enter a single digit from 1 to 9 into each white cell so that the sum of digits in each Across entry equals the value given to the left of the entry, and the sum of digits in each Down entry equals the value given above the entry. No digit may be repeated within a single entry (i.e., group of cells connected horizontally or vertically without any black cells between).
Unlike a standard Cross Sums, where a plus sign is always inserted between all adjacent digits, here a sum may be formed from multi-digit numbers after concatenation, but in each case at least one + sign must be used. In other words, a 24-clue in three cells can be satisfied by an entry like 987 (as 9+8+7 = 24) or 519 (as 5 + 19 = 24) but a 16-clue in two cells cannot be satisfied by 16, since that does not use any addition. Each entry must be able to be formed in only one way (e.g., 40 cannot be written as both 23+17 and 2+31+7).