THE SETUP
The classic Countdown numbers game uses six numbers: a mix of "small" numbers (1–10, sometimes duplicated) and "large" numbers chosen from 25, 50, 75, and 100. A random three-digit target between 100 and 999 is revealed, and you have 30 seconds to combine any subset of the six numbers — using each number at most once — to reach the target.
You can use +, −, ×, and ÷ in any combination. Division only counts if it produces a whole number. You don't have to use all six numbers. Getting within 10 of the target scores partial credit; exact hits score maximum.
GridJoy's Countdown puzzle follows the same format. The mechanics are identical — the difference is that you're solving it on a phone instead of on a set in London.
STEP 1: LARGE × SMALL FIRST
Most experienced players start the same way: multiply a large number by a small one to get close to the target, then adjust from there.
If the target is 432 and you have 75 and 6 in your selection: 75 × 6 = 450. You're 18 away. Now ask: can you make 18 from the remaining numbers? If you have 9 and 2, then 9 × 2 = 18, so 450 − 18 = 432. Done.
The large × small scan covers roughly 70% of all Countdown targets within the first five seconds if you practise it. The large numbers (25, 50, 75, 100) give you a coarse handle on the target range; the small numbers fine-tune.
STEP 2: ROUND-NUMBER PROXIMITY
When large × small doesn't land cleanly, check which round multiple of 25, 50, or 100 is closest to the target. Round-number proximity gives you a mental anchor.
Target 538: the nearest round anchor is 550 (= 100 + 50, or 50 × 11, etc.). 550 − 538 = 12. Can you make 12 from the remaining numbers? If you have 4 and 3: 4 × 3 = 12. So 550 − 12 = 538. Find the anchor, make the difference.
Common anchors worth knowing:
- 100, 200, 300, … (multiples of 100)
- 125, 150, 175, 225, 250, … (multiples of 25)
- 75 × small number (often gets within 50 of most targets)
THE 75-TRICK
If 75 is in your selection, it's worth checking what the target divided by 75 gives you — even roughly. Many Countdown targets are reachable as 75 × n ± small for some integer n.
75 × 1 = 75. 75 × 2 = 150. 75 × 3 = 225. 75 × 4 = 300. 75 × 5 = 375. 75 × 6 = 450. 75 × 7 = 525. 75 × 8 = 600. 75 × 9 = 675. 75 × 10 = 750. 75 × 11 = 825. 75 × 12 = 900. 75 × 13 = 975.
If the target is within 50 of any of these, 75 × n ± adjustment will usually get you there using 2–3 small numbers. The reason this works so well: the "adjustment" from 75 × n to the target is usually small, and small numbers are flexible enough to build most adjustments under 50.
STEP 3: FINE-TUNING WITH SMALL NUMBERS
Once you have a coarse estimate from a large × small product or a round-number anchor, you have 1–4 remaining small numbers to bridge the gap. The gap is usually under 100; often under 30.
To bridge a gap of G with the remaining numbers: check if G is achievable directly as a sum, difference, or small product. The most common fine-tuning patterns:
- Direct subtraction: anchor − one small number = target.
- Small multiply: 2 × 3 = 6, 3 × 4 = 12, 2 × 5 = 10. Gaps that are products of small numbers are easy.
- Sum then adjust: (a + b) subtracted from or added to the anchor.
If none of these work within 30 seconds, take the closest answer you found rather than running out of time with nothing. Partial credit (within 10) often beats opponents who attempt an exact route and overshoot the clock.
WHEN TO APPROXIMATE
In competitive Countdown (and GridJoy's harder difficulties), the optimal strategy isn't always the exact route — it's the fastest reliable route. A solution that gets to within 5 of the target in 10 seconds is often better than an exact solution that takes 25 seconds to verify.
Practise to the point where the large × small scan is automatic. Once it is, you'll find exact routes far more often than approximations — because the scan surfaces most of them immediately, leaving time to verify and refine.
The limiting factor for most players isn't mathematical ability — it's systematic thinking under time pressure. Build the habit of starting with the large number, multiply by the most promising small number, check the gap, fine-tune. That loop runs much faster than random trial-and-error, and it rarely returns nothing.