The question
Question: change 3 m² to square centimeters.
1 Change the length
This square is 1 meter on each side.
Its area is 1 square meter.
1 meter is 100 centimeters.
So each side is 100 centimeters long.
1 m = 100 cm
2 Change the area
So the square holds 100 rows of 100 small squares, each 1 square centimeter.
We draw only a few of them.
So 1 square meter is 100 centimeters times 100 centimeters.
1 m2 = 100 cm × 100 cm
100 times 100 is 10,000.
100 × 100 = 10,000
So 1 m² = 10,000 cm².
Not 100: the 100 comes in twice.
1 m2 = 10,000 cm2
3 Multiply
Each square meter is 10,000 square centimeters.
We have 3 of them, so we multiply: big unit to small unit.
3 m2 = 3 × 10,000 cm2
Careful!
Times 100 only changes a length.
A square has two sides to change: times 100, and times 100 again.
Careful: not 3 × 100 ✗
Times 10,000: write 4 zeros after 3.
× 10,000: the point moves 4 places right
So 3 m² = 30,000 cm².
3 m2 = 30,000 cm2
4 Check
Let's check: go back the other way.
Divide by 10,000.
30,000 ÷ 10,000 = 3
We get 3 square meters again.
So it is right!
Let's look back.
First: change the length.
Then: change the area.
Then: multiply.
Last: check.
▶ Watch it solved
The question
Question: change 25,000 cm² to square meters.
1 Change the length
This square is 1 meter on each side.
Its area is 1 square meter.
1 meter is 100 centimeters.
So each side is 100 centimeters long.
1 m = 100 cm
2 Change the area
So the square holds 100 rows of 100 small squares, each 1 square centimeter.
We draw only a few of them.
So 1 square meter is 100 centimeters times 100 centimeters.
1 m2 = 100 cm × 100 cm
100 times 100 is 10,000.
100 × 100 = 10,000
So 1 m² = 10,000 cm².
Not 100: the 100 comes in twice.
1 m2 = 10,000 cm2
3 Divide
10,000 square centimeters make 1 square meter.
So we divide by 10,000: small unit to big unit.
25,000 cm2 = 25,000 ÷ 10,000 m2
Careful!
Dividing by 100 only changes a length.
For square units it is 100 times 100: 10,000.
Careful: not 25,000 ÷ 100 ✗
Divided by 10,000: the point moves 4 places to the left.
÷ 10,000: the point moves 4 places left
So 25,000 cm² = 2.5 m².
25,000 cm2 = 2.5 m2
4 Check
Let's check: go back the other way.
Times 10,000.
2.5 × 10,000 = 25,000
We get 25,000 square centimeters again.
So it is right!
Let's look back.
First: change the length.
Then: change the area.
Then: divide.
Last: check.
Answer 25,000 cm2 = 2.5 m2
▶ Watch it solved
The question
Question: change 3,000,000 m² to square kilometers.
1 Change the length
This square is 1 kilometer on each side.
Its area is 1 square kilometer.
1 kilometer is 1,000 meters.
So each side is 1,000 meters long.
1 km = 1,000 m
2 Change the area
So the square holds 1,000 rows of 1,000 small squares, each 1 square meter.
We draw only a few of them.
So 1 square kilometer is 1,000 meters times 1,000 meters.
1 km2 = 1,000 m × 1,000 m
1,000 times 1,000 is 1,000,000.
1,000 × 1,000 = 1,000,000
So 1 km² = 1,000,000 m².
Not 1,000: the 1,000 comes in twice.
1 km2 = 1,000,000 m2
3 Divide
1,000,000 square meters make 1 square kilometer.
So we divide by 1,000,000: small unit to big unit.
3,000,000 m2 = 3,000,000 ÷ 1,000,000 km2
Careful!
Dividing by 1,000 only changes a length.
For square units it is 1,000 times 1,000: 1,000,000.
Careful: not 3,000,000 ÷ 1,000 ✗
Divided by 1,000,000: the point moves 6 places to the left.
÷ 1,000,000: the point moves 6 places left
So 3,000,000 m² = 3 km².
3,000,000 m2 = 3 km2
4 Check
Let's check: go back the other way.
Times 1,000,000.
3 × 1,000,000 = 3,000,000
We get 3,000,000 square meters again.
So it is right!
Let's look back.
First: change the length.
Then: change the area.
Then: divide.
Last: check.
Answer 3,000,000 m2 = 3 km2
▶ Watch it solved