What’s been happening recently in the world of mental calculation? What is happening for the rest of 2024? Time for some updates…
Reminder: Mental Math World Cup (online)
This online competition by LiveMCL will be held in July–August 2024 (online) and last year attracted hundreds of participants around the world. Registration closes this year on May 31. All info can be found on the official registration page. Note that the cost is USD $15 per entrant.
The questions are a little easier than for other competitions that I’ve mentioned here, so it’s a good entry point to competitive mental calculation, especially for younger competitors.
Registered entrants can attend some online workshops (I’m running one of them). In addition to the main challenge, participants can choose to participate in the Addition and Subtraction Sprint, the Multiplication Sprint, and the Zen Master Category. Refer to their website for full information.
Please contact the LiveMCL team (not me) if you have any queries.
Reminder: JMCWC and MCWC Registration
If you want to compete in the Junior Mental Calculation World Championship 2024 this September in Bielefeld (Germany), note that registration closes on May 31. All info is in the link above, and here is the official registration page. Please contact Caroline Merkel (not me) if you have any queries.
If you want to compete in the Mental Calculation World Cup 2024 this September in Paderborn (Germany), note that registration closes on June 15. All info is in the link above, and here is the official registration page. Please contact Ralf Laue (not me) if you have any queries. Note that for this competition, supporting documentation (of mental calculation skills) is needed.
GMCA Results + Play-offs in May/June
Since early 2024, Samuel Engel has been organizing a new type of online tournament, consisting ot head-to-head matches. It is now in the final stage: a double-elimination seeded bracket, which will determine the eventul champion. Out of 20 initial participants, some familiar champions are amongst the 10 still competing—as well as some new names like Jure Colak and Rahul Robin.
Check out the latest official results and see some videos of matches.
Hectoc Training Article
To complement the advanced training materials already on this website, I’ve now written a guide to how I solve hectoc questions quickly. Many major competitions have hectoc as a side-event, and it’s a fun alternative to the traditional calculation categories.
New Multiplayer Mental Math Website
I spoken with the creators of MathDash, who have a multiplayer platform for competitive Mathematics. They have some settings specifically for Mental Calculation—just select “Quick Math” from the setting, as “Contest Math” is not mental calculation. I haven’t really used it, but I liked the idea and implementation of the multiplayer arena.
Special Group Multiplication Challenge
Back in November 2023, I announced this informal mental calculation challenge to achieve something in mental calculation that no-one had ever done before (as far as anyone in the community knows): have multiple people work in parallel to solve a large multiplication without writing anything down.
The main challenge was for a team to solve spoken 4-digit multiplications (like 2468 × 7531) mentally without seeing the question, or writing anything down. To help them, they can each do parts of the calculation and combine them.
Although this challenge is very difficult, I had many interesting converations with calculators worldwide, and two successful attempts (I apologize for not publishing the results earlier!)
Extra mention to Greatness Ebiske from Nigeria, who was able to do 5×4 digits solo in about one minute.
Some of the Trendz team in India (Abhilakshya Arora, Agamya Dadhich, Parth Garg, Saksham Garg, Sara Chandani and Tiya Chandani) demonstrated a method that successfully used for 4×4 and 5×5 calculations. Deepak Nagar and Radhika Maheshwari were also involved in analyzing methods.
Their method is to separate one of the multiplicands into separate digits—so, for example, 8536 × 4215 could be done as the following sum:
- 8000 × 4215
- 500 × 4215
- 30 × 4215
- 6 × 4215
The resulting will be 7–8 digits (for 4×4) or 9–10 digits (for 5×5) and so the little end of the sum can be calculated by one person, while the big end is calculated by another. This limits the size of each persons partial sum to 4–6 digits (depending on the question and its size).
Abhilakshya Arora explains their method in this video:
The fastest successful team was arranged by trainer Lata Venkat in the UAE with members in the UAE and India (Asmita Pal, Archita Pal, Raghav Krishna and Madhav Krishna) demonstrated solving 4×4 consistently in 10–20 seconds.
Their method for solving e.g. 8536 × 4215 is:
- Madhav does 36 × 15 = 540
- says: 5__ to Raghav [and remembers 40]
- Raghav does 85 × 15 [1275] + 5 = 1280
- says 1280 to Asmita
- Asmita does 36 × 42 [1512] + 1280 = 2792
- says 27__ to Archita [and remembers 92]
- Archita does 85 × 42 [3570] + 27 = 3597
- begins answer 3597—-
- Asmita says —-92–
- Madhav says ——40
Thanks and congratulations to everyone who had some input into this challenge!
Future Updates
I’ll be back soon with further updates regarding new competition announcements, results of scheduled competitions, and more!