Courses 4. klass
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Matemaatika 4. klass

Discover the world of numbers through the forests, seasons, and stories of Estonia. A Montessori-inspired journey where you learn by touching, building, and exploring mathematics in nature.

4. klass Montessori Estonian Curriculum Ages 10-11
Published
Last updated: Feb 7, 2026
5
Units
24
Lessons
68
Equations
18
3D Visuals
72%
Complete

Course Content

Numbers up to 1,000,000
How many trees are in Lahemaa forest?
Complete
Multi-digit multiplication
Tallinn Old Town cobblestones in rows
Complete
Long division with real objects
Sharing hazelnuts equally among friends
Complete
Order of operations
Recipe steps for kringel pastry
Complete
Word problems — Estonian market day
Shopping at Balti Jaama Turg
Complete
What is a fraction?
Cutting a kohupiimakreem cake into equal pieces
Complete
Halves, thirds, and quarters
Sharing Estonian rye bread at the table
Complete
Equivalent fractions
Same amount, different pieces
Complete
Adding fractions with same denominator
Pannkoogid — Estonian pancake party
Current →
5
Subtracting fractions
How much pie is left?
Locked
6
Fractions in the wild — nature walk
Measuring trees and trails
Locked
Lines, rays, and angles
The clock tower of St. Olaf's Church
Complete
Perimeter — Walking around shapes
Fencing the school garden in Tartu
Complete
3
Area — Covering surfaces
Painting the classroom floor
Locked
4
3D shapes — Boxes, balls, and cones
Building with wooden blocks
Locked
5
Symmetry in Estonian folk patterns
Discovering mirror lines in muhu patterns
Locked
6
Measurement project: Design a park
Your own green space with measurements
Locked
1
Euros and cents in Estonia
Counting coins with Estonian designs
Locked
2
Making change — The lemonade stand
Real transactions with euro coins
Locked
3
Reading clocks and schedules
The Tallinn-Tartu bus timetable
Locked
4
Elapsed time — Planning a Saaremaa trip
How long does the ferry take?
Locked
1
Bar graphs — Bird counting week
Recording birds at your window feeder
Locked
2
Number patterns — Forest growth rings
What comes next in the sequence?
Locked
3
Final project: My Estonian math journal
Combine everything you discovered
Locked
Lesson Progress 0 of 5 sections
1
2
3
4
5
Murdude maailm Lesson 4
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Unit 2, Lesson 4

Adding Fractions

Pannkoogipidu — The Estonian Pancake Party

Section 1 of 5

Close your eyes and imagine...

It's a cold February morning in Tartu. Your grandmother is making pannkoogid (Estonian pancakes) — thin, golden, and warm. The kitchen smells like butter and vanilla. She places a round pancake on a wooden cutting board and picks up a knife...

"How should we share this between you and your sister?" she asks with a smile.

This is where fractions begin — with something real you can touch, cut, and share.

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Hands-On First

Section 2 of 5

Before we write any numbers, try this with a real piece of paper:

  1. 1. Cut a circle from paper — this is your pancake
  2. 2. Fold it in half, then in half again — you now have 4 equal pieces
  3. 3. Colour 1 piece with one colour and 2 pieces with another colour
  4. 4. Count how many coloured pieces you have altogether

You just added fractions with your hands. Now let's discover the pattern.

What does adding fractions look like?

Section 3 of 5

Imagine a pancake cut into 4 equal slices. Mari eats 1 slice. Then she eats 2 more. How much did she eat in total?

1 slice out of 4
+
2 slices out of 4
=
3 slices out of 4
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Did you notice the pattern?

When we add fractions with the same denominator (the bottom number), we only add the numerators (the top numbers). The denominator stays the same!

Think of it like this: the denominator tells you the size of each piece. The numerator tells you how many pieces. If the pieces are the same size, you just count them up!

Worked Example

Section 3 of 5

At the school party in Pärnu, a pie is cut into 8 equal slices. Liis takes 3 slices and Marten takes 2 slices. What fraction of the pie have they eaten together?

Find:
1 Check: do the denominators match?

Both fractions have 8 as the denominator. Yes! We can add them directly.

2 Add the numerators (top numbers)
3 Keep the denominator the same
Answer

Liis and Marten ate 5 out of 8 slices. There are still 3 slices left!

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Practice Time

Section 4 of 5

Use your paper fraction circles or draw pictures to solve these. Write the answer as a fraction.

Problem 1

A kringel (Estonian pretzel) is cut into 6 pieces. You eat 2, your friend eats 1. How much was eaten?

Problem 2

A chocolate bar has 10 squares. Kadri takes 3 and Peeter takes 4. What fraction did they take?

Problem 3

A garden bed is divided into 5 equal rows. Grandpa plants carrots in 2 rows and potatoes in 1 row. How much is planted?

Challenge

A class of 12 students took a vote. 5 chose skiing and 4 chose skating. What fraction voted for winter sports?

All Solutions:

  1. 1. 3/6 (or simplified: 1/2)
  2. 2. 7/10
  3. 3. 3/5
  4. 4. 9/12 (or simplified: 3/4)
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Fractions in Estonia

Fractions are everywhere around you. Here are some real examples from Estonian life:

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Estonian forests

About of Estonia is covered by forest — one of the highest in Europe!

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Estonian islands

Estonia has over 2,000 islands. Saaremaa covers about of all island area.

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School day

If your school day is 6 hours, and math class is 1 hour, math is of your day.

What you discovered today

Section 5 of 5
✓ When fractions have the same denominator, you add only the numerators
✓ The denominator tells you the size of each piece — it stays the same
✓ You can always check your answer by drawing or cutting paper circles
Geomeetria ja mõõtmine Lesson 2
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Unit 3, Lesson 2

Perimeter — Walking Around Shapes

Fencing the school garden in Tartu

A question from the schoolyard...

Your class at Tartu Kivilinna School wants to plant a sunflower garden. The garden is a rectangle: 8 metres long and 5 metres wide. You need to buy fence to go all the way around it.

How many metres of fence do you need?

Before you calculate — go outside and walk around a rectangular area. Count your steps. That is what perimeter feels like.

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Hands-On First

  1. 1. Take a piece of string or yarn (about 1 metre)
  2. 2. Lay it around the edge of your desk to form a rectangle
  3. 3. Straighten the string out and measure it with a ruler
  4. 4. Now measure each side of your desk separately and add them up

Did you get the same answer both ways? That's perimeter!

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Discovery

Perimeter is the total distance around the outside of a shape. It is like taking a walk along every edge.

The School Garden

🌻 🌻 🌻 🌻 🌻 8 m 5 m 8 m 5 m 🚶

The green dashed line shows the fence around the garden. The person walks along every side.

Step-by-Step Solution

How much fence for the garden?
1 Identify all four sides

A rectangle has 2 long sides (length) and 2 short sides (width).

2 Add all four sides together
3 Calculate
Answer

You need 26 metres of fence for the sunflower garden!

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A faster way

Since a rectangle always has two pairs of equal sides, there's a shortcut:

Multiply by 2 because you walk along each measurement twice — once on each opposite side.

From 2D to 3D

What if the garden had walls? Then it would become a 3D shape called a rectangular prism (a box). You can explore it below.

8m x 5m x 3m

A rectangular prism (box shape) — the garden with walls! In later lessons, you'll learn to calculate the perimeter of the base, the surface area, and the volume.

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Try It Yourself

Problem 1

A classroom window is 2m wide and 1m tall. What is the perimeter of the window frame?

Problem 2

The football field at your school is 90m long and 45m wide. How far is one lap around the edge?

Problem 3

A square tile on the kitchen floor is 30cm on each side. What is its perimeter?

Challenge

You have 20m of ribbon. Can you make a border around a rectangle that is 6m long and 4m wide? Is there ribbon left over?

Think: P = 2 x (6 + 4) = ?

What you discovered today

✓ Perimeter is the total distance around the outside of a shape
✓ For a rectangle: add all 4 sides, or use
✓ Always include units in your answer (metres, centimetres)
✓ You can check by measuring with string — the hands never lie!