Chapter II – Comparing Numbers
Comparing numbers is one of the key mathematical skills developed in early primary education. It forms the foundation for understanding the concept of number, its value, order, and the relationships between numbers. A child who can identify which number is greater, smaller, or equal to another gains the basis not only for performing calculations but also for solving word problems, logical tasks, and practical everyday situations.
In grades 1–3, the development of this skill should take place in a concrete way, using tangible, countable objects. Only then does the student have the opportunity to truly understand what it means that there is “more” or “less” of something—not as an abstract notation, but as a real action and observation.
Korbo blocks perfectly support the development of this skill because they:
enable building numerical sets and comparing them through hands-on activity,
allow children to count, arrange, order, and compare elements in an active and independent way,
introduce the possibility of modeling numerical concepts by assigning values to individual elements (e.g. a cylinder as 5, a platform as 10),
support the development of logical, spatial, and language skills when students describe their constructions and comparisons.
Construction-based activities using Korbo blocks make it possible to achieve educational goals aligned with the core curriculum, while at the same time giving children the joy of action, experimentation, and discovering mathematical principles in practice.
After completing the tasks in this chapter, the student:
Compares natural numbers within a range appropriate for their grade, using the terms: more, less, the same.
Records numerical comparisons using mathematical symbols: >, <, =.
Creates and reads sets with equal quantities, using different types of elements (e.g. cylinders, gear wheels).
Orders numbers in ascending and descending order based on the number of elements in a set or construction.
Creates constructions with a specified number of elements and compares them with constructions made by other students.
Builds sets with a specified numerical difference (e.g. a set that is larger by 3).
Makes estimated and exact comparisons of the number of elements in sets or the height of constructions.
Creates number models using Korbo elements by assigning values (e.g. cylinder = 5, platform = 10).
Solves simple word problems involving number comparison, such as “How many more?” or “How many fewer?”
Communicates the results of comparisons verbally and graphically, for example orally, on paper, using symbols, or through constructions.
Task 1. Who Has More?
Objective: Comparing the number of elements in sets.
Required elements: gear wheels, cylinders, connectors, dice or math dice.
Procedure:
Children work in pairs. Each child rolls a die and selects the indicated number of elements. They then compare their sets and determine who has more, who has fewer, or whether they have the same number, as well as how many more or how many fewer.
Variations:
Children can roll two dice, first adding the rolled values and then selecting the corresponding number of blocks.
Pair activity: children can be given cards with the symbols >, <, = and place the appropriate symbol between their own blocks and their partner’s blocks.
2. Build and Compare
Objective: Comparing the number of elements in constructions.
Required elements: gear wheels, cylinders, platforms.
Procedure:
Children work in pairs and build constructions using any number of blocks within a set time (e.g. 30 seconds). They count how many elements they used and compare their structures to determine which has more, fewer, or the same number of parts.
Variations:
Children build only a pyramid made of cylinders, stacking them one on top of another (in the shape of a pyramid).
3. Comparison Tower
Objective: Comparing height as a result of the number of elements.
Required elements: cylinders.
Procedure:
Each child builds a tower using selected elements. They compare the towers in terms of the number of blocks and their height—identifying which tower is taller and which has more elements.
Variations:
On each cylinder, a gear wheel must first be placed (without pressing it into the opening), and only then can another cylinder be added.
Building towers with a specified difference (e.g. “The teacher’s tower has 3 blocks; your towers should be 2 blocks taller”).
4. Platform Scale
Objective: Assigning numbers to the length of constructions.
Required elements: platforms, gear wheels.
Procedure:
Children build rows of gear wheels on a platform, arranging them horizontally. Each row represents a number (e.g. a row of 4 gear wheels = 4). The children then compare the lengths of the rows.
Variations:
Building increasing or decreasing sequences on a large platform (e.g. 10 rows on 10 platforms).
5. Who Is Faster? – Gear Clock
Objective: Comparing time and the number of rotations.
Required elements: gear wheels, one platform, a marker built from cylinders, a straight connector, and a cross connector (in an inverted L shape).
Procedure:
Children spin a gear wheel and count how many rotations it makes in 30 seconds. They compare the numbers to determine who made more rotations and who made fewer.
Variations:
Changing the time interval or the hand used (e.g. 10 seconds, 1 minute).
Adding word problems, such as: “If I made 5 rotations and you made 7, who made more and by how many?”
6. Number Battle
Objective: Comparing randomly selected numbers.
Required elements: a box of blocks, cards with numbers.
Procedure:
Children approach the box and take a “handful” or a “bucket” of blocks, then count how many they have of a given type. They compare the results in groups. This can be played as a point-based game—the person or group with the larger number wins.
Variations:
The teacher can draw counting challenges, for example: which group has the most cylinders, connectors, red gear wheels, etc.
7. Encode the Number
Objective: Encoding and comparing numbers.
Required elements: gear wheels, cylinders, platforms.
Procedure:
Together with the children, assign values to individual elements, for example:
A straight connector has a value of 1, a gear wheel has a value of 2, a cylinder = 3, a cross connector has a value of 4, a platform has a value of 5, etc. Coding cards can also be used.
The children’s task is to build a construction with a total value of, for example, 35. Then the constructions are compared to see which one is taller, which is wider, and so on.
Variations:
During construction, restrictions can be introduced, for example: “You may not use more than 2 cylinders.”
8. Growing Line
Objective: Ordering numbers in ascending and descending order.
Required elements: different numbers of blocks placed in bags, one bag per group.
Procedure:
Each group places its set of blocks next to each other in a single row. Then the children arrange the rows in ascending or descending order. The blocks are counted.
Variations:
Rearranging the rows in ascending order while taking into account the number of cylinders that were in the bags.
9. Equal but Different
Objective: Creating sets with equal numbers using different elements.
Required elements: gear wheels, cylinders, platforms.
Procedure:
Children create two sets that contain the same number of elements but differ in the type of blocks used (e.g. 3 cylinders = 3 gear wheels).
Variations:
Pair activity: one partner guesses whether the sets are equal (first comparing “by eye,” without counting, and then checking by counting).
10. Build the Difference
Objective: Identifying the difference between numbers.
Required elements: various Korbo elements.
Procedure:
The student is given two numbers (e.g. 8 and 5). They build two sets with the corresponding number of elements and represent the difference by adding or removing the missing blocks.
Variations:
Reverse tasks: one child builds the difference and another child guesses the numbers.
Changing the number range (e.g. up to 20, up to 50).