The case notes
How a run-sum clue works
The outside clue sums each row digit that has a consecutive digit immediately beside it. A digit with two consecutive neighbours is counted only once. Watch a worked example, then try the idea in a puzzle.
Put it into practice
Count consecutive neighbours
A run-sum clue looks along a row or column. Count any digit that sits beside a consecutive digit: a neighbour one higher or one lower.
6 + 7 + 8 = 21
Six, seven and eight sit together. Each touches a consecutive neighbour, so all three count. Seven counts once, even though it touches both six and eight.
3 + 4 would make 28 total
The row still needs two and four in these open cells. If four follows the three, that pair adds seven. With the first run, the total would be twenty-eight, too high.
21 + 3 + 2 = 26
Put two after the three instead. Three and two add five. Twenty-one plus five is the clue, twenty-six; four takes the last open cell.
Mark, then add once
Mark every digit with a consecutive neighbour, then add each marked digit once. The outside clue is their total.
Read the transcript
A run-sum clue looks along a row or column. Count any digit that sits beside a consecutive digit: a neighbour one higher or one lower. Six, seven and eight sit together. Each touches a consecutive neighbour, so all three count. Seven counts once, even though it touches both six and eight. The row still needs two and four in these open cells. If four follows the three, that pair adds seven. With the first run, the total would be twenty-eight, too high. Put two after the three instead. Three and two add five. Twenty-one plus five is the clue, twenty-six; four takes the last open cell. Mark every digit with a consecutive neighbour, then add each marked digit once. The outside clue is their total.
