More or Less: Is this Premier League striker a secret maths genius?

BBC Radio 4 | Host: Tim Harford | Date: February 7, 2026

Episode Overview

In this lively episode, Tim Harford explores an unexpected mathematical talent in the world of Premier League football. The featured question: is striker Liam Delap secretly a maths genius, or can his headline-grabbing cube root "party trick" be learned by anyone? Author and maths enthusiast Rob Eastway joins Tim to break down the mental maths behind Delap’s feats, reveal the patterns at play, and discuss recent trends in Premier League goal tallies.

Key Discussion Points & Insights

Liam Delap’s Cube Root Trick: Maths Genius or Memorable Method?

• Introduction to the “Trick” (01:18–02:54)

  • Tim Harford introduces viral clips of Liam Delap astonishing fans by instantly naming cube roots of large numbers.
  • Example: Delap correctly states the cube root of 79,507 is 43, and 778,688 is 92.

    “Just clever, isn’t it?” – Tim Harford (02:54)

• Demonstration and Explanation (03:01–07:30)

  • Rob Eastway explains that Delap’s party trick doesn’t require genius—just a clever system and memory tricks.
  • Step-by-step Guide:
    1. Memorise Cubes 1–9:
       • Example: 3³ = 27, 7³ = 343, 9³ = 729, etc.
       • “You’ve only got two to learn.” – Rob Eastway (04:31)
    2. Find the First Digit:
       • Look at the thousands grouping of the number, find the largest cube below it, and its root is your first digit.
         • E.g., For 274,625, look at 274; 216 (6³) is the nearest lower cube. So, the first digit is 6.
         • “So, 6 is our first number. That’s a bit complex, admittedly, but luckily it gets easier.” – Tim Harford (05:13)
    3. Find the Second Digit:
       • The last digit of the cubed number will always relate to the last digit of its cube root in predictable ways. Most numbers cycle or “swap” their final digits when cubed (except for 3 & 7, 2 & 8, which swap).
         • Example: Any number ending in 4 (when cubed) will still end in 4.
         • “The last digit of a cube number is always going to be predictable.” – Tim Harford (06:39)
         • So for 274,625 (ends in 5, starts in 6), answer is 65.
         • “You’re a genius. Or you’ve got a good memory, but I’m going to go with the first.” – Rob Eastway (06:58)

• Deeper Meaning or Party Piece?

  • Rob Eastway: These kinds of maths tricks showcase pattern-spotting and the beauty of numbers. While not “deep maths,” it reveals the entryways into mathematical thinking.
    • “It’s rather beautiful. And it’s a party trick.” – Rob Eastway (07:08)

Premier League Goals: Predicting and Explaining the Numbers

• Rob’s Prediction vs. Reality (07:52–09:09)

  • Rob Eastway recalls predicting roughly 1,000 goals per Premier League season (±5%).
  • Recent seasons smashed this, reaching 1,084 then 1,246.

    “That was nothing compared to 2023/24 when the 1,246. We weren’t even in the same amount.” – Rob Eastway (08:24)

• What Changed? Regulation and Real Play Time

  • Primary cause: FIFA’s push to tighten up on time-wasting after the 2022 Qatar World Cup.

    “Time wasting is a real problem. We must stop it ... So suddenly games became longer, quite a bit longer.” – Rob Eastway (08:48)

  • On average, ball-in-play time increased from 55 to just over 58 minutes—a 6% rise (2022/23 to 2023/24).
  • However, goals per match jumped about 15%, so more than just longer games—tactical and player quality changes may play a part.

    “Football’s a complex game and anything from changes in tactics to differences in player quality may well have had an effect.” – Tim Harford (09:17)

• Liam Delap’s Contribution

  • In the 2023/24 season, there were 1,180 goals; Delap scored 12 (about 1%).

    “That is very impressive. And he was playing for Ipswich at the time, so even more impressive.” – Rob Eastway (09:54)

Notable Quotes and Memorable Moments

• On Learning Maths Tricks:

  • “You can’t do it yet. You’re going to be able to do this very soon.”
    – Rob Eastway, on Tim’s initial lack of confidence in mental cube roots (03:44)

• On the Predictability of Cubes:

  • “So the message of this is that the last digit of a cube number is always going to be predictable.”
    – Tim Harford (06:39)

• On the Broader Appeal of Maths:

  • “It’s one of those little pathways into numbers and the beauty of numbers and the fact that we’re spotting patterns.”
    – Rob Eastway (07:08)

• On Football’s Changing Patterns:

  • “Football’s a complex game and anything from changes in tactics to differences in player quality may well have had an effect.”
    – Tim Harford (09:17)

Key Timestamps for Important Segments

| Time | Segment | |-----------|---------------------------------------------------------------| | 01:18 | Introduction to Liam Delap’s cube root trick | | 03:01 | Rob Eastway explains the cube root “party trick” | | 04:05 | Memorising cubes 1–9; first digit of the cube root explained | | 05:48 | Second digit trick and digit patterns for cubes | | 07:30 | Transition to Premier League goal statistics | | 07:52 | Rob’s goal prediction and recent record-breaking seasons | | 08:46 | Changes in football regulations and play time | | 09:49 | Delap’s goal tally and contribution |

Takeaways

• Anyone can learn Delap’s “maths genius” cube root trick with pattern recognition and a bit of memory work.
• Maths patterns aren’t just academic—they’re fun party tricks and illustrate the beauty of logical thinking.
• Premier League goal statistics can be upended by factors like regulation changes and longer playtimes.
• Even with new regulations, complexities in football (tactics, skills, etc.) mean numbers (like goals per season) may not follow predictions.

Guests:

• Rob Eastway, author of Maths on the Back of an Envelope

Contact:

• Questions or comments: moreorless@bbc.co.uk

Tone:
Witty, inquisitive, and accessible—maths and football made fun for everyone.