Daily estimation puzzle

Fermi Answer Today

Three questions. Three surprising answers. Reveal each answer when you’re ready, then see how Fermi estimates it.

Fermi #1023 questions

A little help for today’s big questions.

1QUESTION 1 OF 3

Lay every string from a 9-foot (2.7 meter) Steinway Model D concert grand end to end. How long is all the string?

Counting only the part of each string that vibrates.

Steinway Model D concert grand

Steinway Model D concert grand

A black Steinway & Sons concert grand on a stage with its lid raised, showing the long strings fanning out over the gold frame inside, beside a black piano bench

Illustration from Fermi.gg

Reveal answer & explanation

Official answer

520

feet

How to estimate it

Fermi’s official “Napkin math”

Start with the 88 keys, most of which hit 3 strings. How long is a typical string? The longest is maybe 6 feet and the high notes are only inches, so call it 2 feet.

88 keys × 3 strings
≈ 260 strings
Typical string
≈ 2 feet
260 × 2
≈ 520 feet

Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.

Source calculation & reference
Steinway D strings (8 single, 12 double, 68 triple)
236
Longest, agraffe to bridge (Steinway)
79.25 in (201 cm)
Vibrating lengths summed, INRIA table
158 m
≈
520 feet

Reference cited by Fermi: Our sum of INRIA's Steinway D string lengths (Chabassier and Durufle, 2012)

Full answer & compare your estimate
2QUESTION 2 OF 3

How many active lawyers live in Alaska?

Reveal answer & explanation

Official answer

2,262

lawyers

How to estimate it

Fermi’s official “Napkin math”

The easiest place to start is Alaska's population, which is small, about 700,000. How many of them are lawyers? Not many. Call it 1 in every 250 people.

Alaska population
700,000
Share who are lawyers
1 in 250
700,000 ÷ 250
≈ 2,800

Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.

Source calculation & reference
Alaska Bar members, all statuses
4,990
Active and living in Alaska
2,262
Cross-check, ABA resident active count (2024)
2,294
≈
2,262

Reference cited by Fermi: Alaska Bar Association membership statistics

Full answer & compare your estimate
3QUESTION 3 OF 3

How many ears of field corn grow on one acre (0.4 hectare) of a typical US cornfield?

Reveal answer & explanation

Official answer

29,000

ears

How to estimate it

Fermi’s official “Napkin math”

An acre is about 44,000 square feet. Corn rows sit about 2.5 feet apart. How close are the stalks in a row? Maybe 6 inches, so each stalk gets a bit over a square foot and grows one ear.

One acre
44,000 sq ft
2.5 ft × 0.5 ft per stalk
÷ 1.25 sq ft
44,000 ÷ 1.25
≈ 35,000

Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.

Source calculation & reference
USDA NASS ear counts, 10 States, 2025 final
28,550 per acre
Same survey, October 2026
28,600 per acre
Plants per acre, 2025 final, about 1 ear each
28,800
≈
29,000

Reference cited by Fermi: USDA NASS Crop Production, objective yield survey: 28,550 ears per acre (10 States, 2025)

Full answer & compare your estimate

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Fermi.gg is a daily estimation game with three numerical questions. Start with a rough guess, break the problem into smaller pieces, and aim to get as close as possible. A new puzzle arrives at midnight New York time.

An independent answer guide. Questions, illustrations and official explanations are credited to Fermi.gg.

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