Equation: STILL + WITHIN = LIMITS. Each of the 8 unique letters (H, I, L, M, N, S, T, W) represents a different digit. Leading letters (S, W, L) cannot be zero.

S=9, T=7, I=1, L=6, W=5, H=0, N=3, M=4 → 97166 + 517013 = 614179

STILL + WITHIN = LIMITS

What is this puzzle?

Solve the addition alphametic puzzle where STILL + WITHIN = LIMITS. Each letter represents a unique digit from 0-9. No number starts with zero.

Difficulty: medium · Category: addition · Unique letters: 8

This medium-level addition alphametic puzzle features 8 unique letters (H, I, L, M, N, S, T, W). In the equation STILL + WITHIN = LIMITS, each letter maps to a distinct digit from 0 to 9. With only 8 of 10 digits used, 2 digits remain unused in the solution. The leading letters S and W and L cannot represent zero — this is your first constraint. To solve this efficiently, focus on letters that appear in multiple positions across the equation — these are the most constrained and often the easiest to determine first.

This addition alphametic has 8 unique letters to determine.
Leading letters: S, W, L. None of these can be zero.
There are 8 unique letters, so 2 digits from 0–9 will not be used.
Start from the rightmost column (units place) and work left, tracking carries between columns.
With two addends, each column can produce a carry of at most 1.
A moderate number of letters means you'll need logical deduction alongside trial and error.