Counting paths on a grid

When you may only move right and down, the number of routes to a point is the number of routes to the square above plus the number to the square on the left. Writing that number into every square fills the grid and the corner holds the answer.

Your progress

Not started

1Not started
0Familiar
0Proficient
0Mastered

Saved in this browser only. No account, nothing sent anywhere.

Work through it

LearnWhat it is, how to spot it, a worked example, and where it goes wrong.
Practice — 3-point ladderNo problems written at this tier yet.Nothing written at this tier yet
Practice — 4-point ladderNo problems written at this tier yet.Nothing written at this tier yet
Practice — 5-point ladder1 problem. Three in a row finishes it.0/3 in a row · 0/1 solved
Skill quizFinish every ladder that has problems first.Finish the ladders above first

Before and after

Needs first

CNT-03The multiplication principle GEO-02Grid coordinates and lattice reasoning

Opens up

Nothing yet. No other skill in the Atlas lists this one as a prerequisite.

In official papers

No indexed official paper question has been tagged with CNT-07 yet. The index grows one paper at a time, and it records only question numbers, point values and our own skill tags — never the problems themselves.

See the papers indexed so far

Loading…