Silent mathematical wall clock with black background — ALGORA
Tax included
In the box
- 1 wall clock with quartz movement
Everything you need to know
Le Labo Wall clock To tell the time, you will first have to do a little math: the ALGORA mathematical wall clock replaces every number on the dial with an operation to solve. At the top, 6·2 indicates twelve o'clock; elsewhere, a square root, a proportion, or a small equation replaces the familiar hours. The expressions are traced in white chalk-style script on a deep black background, like a classroom blackboard, and two white hands move across this scholarly dial. Powered by a silent quartz movement, it stays quiet at night or in meetings, without a ticking sound. The light wood back features a mounting notch for easy installation. Four diameters are offered, from approximately 25 to 40 cm, to suit a study, student bedroom, classroom, or large living room wall. A clock that makes math lovers smile, intrigues visitors, and turns every glance at the time into a quick mental math exercise.
The four available diameters
The dial, hands, and movement are identical across all four sizes: only the diameter changes. The larger the clock, the more legible the operations remain from a distance, an asset in a classroom or a shared workspace.
Telling time by calculating: the dial principle
On a classic dial, each hour is indicated by a number from 1 to 12. ALGORA keeps this exact logic, but each position is occupied by an expression whose result corresponds to the hour. At the top of the dial, 6·2 gives 12; √4 gives 2; the proportion 50/2 = 100/x is solved with x = 4; √49 gives 7; and the equation -8 = 2 - x is solved with x = 10. The other positions follow the same principle, with square roots, subtractions, or first and second-degree equations.
This type of dial is a cheeky tribute to math education: it reminds us that familiar numbers can be written in a thousand ways. Incidentally, the time is very easy to read without solving the calculations, thanks to the position of the hands, just like on a clock with a blank dial. Solving the operations then becomes an optional game, which can be proposed to a child, a student, or a curious guest.
Why you will love it
When time becomes a puzzle
There is something joyfully provocative about this clock. Where one expects a simple 12, one reads 6·2; where one expects a 7, a square root. Visitors stop, squint, calculate, then smile. The black dial with white inscriptions immediately evokes a school blackboard, chalk, and demonstrations during a lesson.
However, once hung, the object is not school-like at all: its sober black-and-white graphic design fits into a contemporary office, a library, or a kitchen. ALGORA is the clock for those who love numbers, riddles, and objects that tell a story. A discreet way to remind us every day that math can also be fun.
Installing your ALGORA clock
ALGORA or Blackboard clock?
| Criteria | ALGORA (this clock) | Blackboard equation clock |
|---|---|---|
| Dial | Solid black background, white chalk operations | Black background covered in calculations, school blackboard style |
| Expressions | Multiplication, roots, proportions, equations | Factorials, derivatives, determinants, summation, roots |
| Level | Mental math, middle school and high school | More advanced, high school and higher education |
| Diameters | Approx. 25, 30, 35 or 40 cm | 30 cm |
| Frame | Frameless, light wood back | With metal frame and acrylic glass, or frameless |
| Movement | Silent quartz, 1 AA battery | Quartz, battery not included |
Le Labo offers a second mathematical clock, with a blackboard-style dial covered in more advanced formulas. To discover it along with our other timekeeping objects, visit the time and weather objects collection.
Good to know: the AA battery is not included. The indicated diameters are rounded: according to the manufacturer's comparative photo, they correspond approximately to 24.7 cm, 29.7 cm, 34.7 cm, and 40.6 cm. The supplier specifies "bamboo and wood" materials; the light wood back is visible in the photos.
Tip: in a child's bedroom or a classroom, hang the clock at eye level and offer a small challenge: find the result of each operation. It's a playful way to review square roots, proportions, and equations, without it feeling like work.
Technical characteristics
| Type | Round wall clock with mathematical dial |
| Dial | Black background, operations in white chalk-style writing |
| Hands | White (hours, minutes) |
| Diameters | 25, 30, 35 or 40 cm (10, 12, 14 or 16 inches) |
| Movement | Silent quartz |
| Power supply | 1 AA battery (not included) |
| Back | Light wood with hanging notch |
| Materials (supplier) | Bamboo and wood |
| Mounting | Wall, via notch |
| Thickness | Not disclosed |
| Weight | Not disclosed |
Precautions: keep the battery out of reach of children: if swallowed, consult a doctor immediately. Remove the battery if not in use for a long period and dispose of it at an appropriate collection point. Attach the clock to a support suitable for the type of wall; avoid very humid rooms and direct sunlight, which could alter the dial and wood.
A clever gift for number lovers
ALGORA is the ideal gift for a math teacher, engineer, student, or puzzle enthusiast. It marks a school year start, exam success, retirement, or moving into a first office.
To put together a science-themed gift, explore Le Labo's scientific objects or our puzzles and desk items.
Frequently asked questions
How do you tell time on this math clock?
The hands work exactly like on a classic clock: the short one points to the hours, the long one to the minutes. The only difference is the dial: each number from 1 to 12 is replaced by an operation whose result corresponds to the hour. At the top, 6·2 equals 12; √4 equals 2; √49 equals 7, and so on. You can therefore read the time without calculating, simply by the position of the hands, just like on a blank dial. Solving the operations becomes an optional little game, which amuses adults as well as students, making every glance at the time a bit more stimulating.
Does the clock make noise?
No, or almost not at all. ALGORA is equipped with a silent quartz movement, marketed by the manufacturer as "super silent." Unlike classic ticking movements, the second hand, when present, or the mechanism do not produce audible clicking at a normal distance. This is an important asset for a bedroom, office, library, or meeting room, where the steady sound of a clock can quickly become annoying. In a perfectly quiet room, by pressing your ear against the dial, a very faint sound from the motor might remain, but it stays imperceptible in daily use, including at night.
Which diameter should I choose?
The choice depends mainly on the viewing distance and the size of the wall. The 25 cm is suitable for an office, bedroom, or small wall section, when you are within two or three meters. The 30 cm is the most versatile format, perfect for a kitchen or home office. The 35 cm stands out in a living room or meeting room. Finally, the 40 cm is ideal for a large wall or classroom: the operations remain legible from afar, which facilitates the calculation game. The exact dimensions, according to the manufacturer's photo, are slightly different from the rounded values.
What battery does it need and is it included?
The clock runs on a single AA battery (LR6), a common format that is easy to find. It is not included: remember to provide one before installation, especially if you are giving it as a gift. The battery is inserted into the quartz movement housing on the back of the clock, observing the indicated polarity. A good quality alkaline battery generally ensures long life for this type of quartz movement, though we cannot provide an exact duration. When the clock starts to run slow or stops, simply replace the battery and reset the time using the wheel.
How do I hang the clock on the wall?
The back of the clock, made of light wood, features a hanging notch intended for a nail or screw. Choose a fixture suitable for your wall: wall plug and screw for drywall or hollow brick, nail or hook suitable for a solid wall. Position the clock at eye level to enjoy the dial's operations, then check that it is level using the top number (6·2) as a reference. Avoid very humid areas, like above a shower, as well as direct sunlight. The mounting hardware is not included: a simple nail or screw is sufficient in most cases.
How is this different from Le Labo’s other math clock?
Le Labo offers two distinct mathematical clocks. ALGORA has a solid black background on which operations accessible via mental math stand out: multiplication, square roots, proportions, and simple equations. It comes in four diameters, from approx. 25 to 40 cm, with a light wood back. The other model features a school blackboard-style dial entirely covered in calculations, with more advanced expressions (factorials, derivatives, matrix determinants, summations); it measures 30 cm and is available with a metal frame and acrylic glass or without a frame. ALGORA is more graphic and accessible, the other more dense and scholarly.
Is this clock suitable for a classroom?
Yes, it is actually one of its favorite uses. Its blackboard-style dial fits naturally into a math room, and its operations offer a playful aid for reviewing mental math, square roots, and equations. For a classroom, we recommend the 40 cm diameter, or 35 cm, so that students can read the expressions from the back of the room. The silent quartz movement prevents any distracting noise during lessons or exams. It also makes an appreciated gift for teachers at the end of the school year, whether for the classroom or their own office.
