Implication is one of the advanced techniques. It works with Booleans and requires the establishment of hypotheses. It produces a simplification of the number of Booleans. It is an extremely powerful instruction and is widely used in puzzles marked “often difficult.” The implication is not easy to understand. To help, we can translate it with […]
Invariance is one of the advanced techniques. It requires the establishment of hypotheses. We choose empty cells (or cells containing Booleans) and successively set them to true and false, then observe the result. Let A and B be two empty boxes or boxes containing booleans. If, whatever the true or false state of A, B […]
Actilud is a website offering mathematical manipulation games, aimed at primary and secondary school students, teachers and trainers, and puzzle enthusiasts. Actilud is free to access and free of advertising or trackers: my modest contribution to an open and free educational Internet. The introductory video (in french for the moment) provides a tour of the […]
In the Numbers and Operations section, you will find an assortment of abacuses available for free work, group use, or individual exercises. The counting abacus The counting abacus on Actilud uses the same codes as a traditional children’s abacus. It consists of 10 rows of ten tokens, each token worth one unit. There is no […]
The game “Mass and Weight Across the Solar System” helps you understand the difference between mass and weight. It’s also a good way to practice the concept of framing. Through the game’s genesis, this article details the principles involved and their consequences. Finally, we’ll understand why it’s difficult to weigh a lemon on Phobos. The […]
Numbers are hidden and form a circuit. Each number is separated from the next by an operation. To find the numbers, all the operations must match. Three circuits of 3, 4 and 6 stages The basic rules Numbers are all natural integers between 1 and 100. This rule is fundamental! It allows you to frame […]
Places a true or false sign at the intersection of a row and a column. This is the basic instruction of zebra puzzles. Alice is third. Bob is wearing a yellow jersey. Fifth doesn’t drink apple juice. When a true sign is placed, the row and column of the intersection can be completed with false […]
The threshold instruction compares a subject to a value in an ordered series. It randomly sets a threshold in the series, beyond which values are false. This is an easy instruction, recommended for simple zebra puzzles. To use it, at least one ordered series is required. The threshold instruction does not require the series to […]
Make a vague comparison between two items a and b sharing a common ordered series. This instruction is one of the few that cannot use Booleans; it requires a traditional resolution: returning to the statement several times. This is why this type of comparison is called vague. The common ordered series does not need to […]
Establishes a precise anteriority relationship between two items a and b, both using a series C containing an order relationship. The series C allows to indicate a constant distance d, which appears between a and b. To use it, you therefore need at least one ordered series. The series does not need to be regular. […]
Establishes a precise anteriority relation between three items a, b, c, all three using a series D containing an order relation. The series D allows to indicate two constant distances d 1 and d 2 , which appear between a and b for d 1 , b and c for d 2 . To use […]
Create a gap between two items a and b using a regular ordered series. To use it, you therefore need at least one regular ordered series. To make solving easier, Booleans are recommended. This is one of the most complex instructions in zebra puzzles. Ordered series: A series containing values that are all increasing or […]
Creates an alternative regarding a given topic. The alternative can take place in a single grid or across two grids. When the alternative concerns a single grid, there is no need to use Booleans: false signs are sufficient. When it concerns several grids, Booleans must be used with the grid of alternatives. The alternatives translate […]
Performs a sum s of the items chosen from two summable series A and B. If there are more than 2 summable series, they will be drawn randomly. The SUM instruction allows you to choose the subject heading. To use it, you therefore need at least two summable series. To facilitate resolution, Booleans are recommended. […]
Perform a sum s of the items chosen from all summable series. At least two are required. The subject is chosen from the remaining non-summable series. The TOTAL instruction may require waiting until the boxes are more or less filled before using the Booleans. Indeed, it may not be usable from the beginning of the […]
The Turing machine is a mathematical model developed by the famous mathematician Alan Turing in 1936. The model is generally presented as a way to demonstrate the capabilities of a computer. What a Turing machine can do, a computer can—or will be able to—do. What a Turing machine cannot do, no computer will ever be […]
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