There are six children playing on a playground. Each child has two keychains. What is the ratio of children to keychains?

There are 6 children * 2 keychains/child = <<6*2=12>>12 keychains.

The ratio of children to keychains is 6 children / 12 keychains = <<6/12=0.5>>0.5 children/keychain. Answer: \boxed{0.5}.

To find the ratio of children to keychains, we need to determine the total number of children and the total number of keychains.

Given that there are six children playing on the playground, each child having two keychains, we can calculate the total number of keychains as:

Total number of keychains = Number of children × Number of keychains per child
Total number of keychains = 6 children × 2 keychains per child
Total number of keychains = 12

So, there are 12 keychains in total.

Now, we can calculate the ratio of children to keychains by dividing the total number of children by the total number of keychains:

Ratio of children to keychains = Total number of children / Total number of keychains
Ratio of children to keychains = 6 children / 12 keychains
Ratio of children to keychains = 1/2

Therefore, the ratio of children to keychains is 1:2.

To find the ratio of children to keychains, we need to determine the total number of children and the total number of keychains.

Given that there are six children and each child has two keychains, we can multiply the number of children by the number of keychains per child to find the total number of keychains.

Total number of keychains = 6 children * 2 keychains per child
Total number of keychains = 12 keychains

Now that we know there are 12 keychains, we can express the ratio of children to keychains as follows:

Ratio of children to keychains = Number of children : Number of keychains
= 6 : 12

However, we can simplify this ratio by dividing both numbers by their greatest common divisor, which in this case is 6.

Simplified ratio of children to keychains = 6/6 : 12/6
= 1 : 2

Therefore, the ratio of children to keychains is 1 : 2.