The scale tells you how much smaller a plan or a model is than reality.
1:100 means: 1 cm on the plan is 100 cm in real life.
This is how you do it:
1. Check which scale applies.
2. From the model to reality you multiply.
3. From reality to the model you divide.
The number written in shows the answer.
Example
Scale 1 : 100
4 cm →400cm
5 cm →500cm
For parents
What does this exercise practice?
This exercise links understanding of quantities with multiplying and dividing and prepares reading plans and maps.
Common pitfalls
Children often mix up the direction. The question of whether the result has to be bigger or smaller than the starting number helps.
How to practice at home
Look for scale details like 1:100 on maps, building plans and toys and work out together how big reality is.
Related: Converting Units, Comparing Measurements, Measuring lengths