i don't know how to answer ,stage 3 out of 3 "Things that count" python

you need to use the format function.

you can use the format function on a string by placing {} inside a string and calling .format() on the string itself. you can pass in variables to the format function and their values will be inserted where the {} are.

for example, If I had two variables named x with a value of "py" and y with a value of "thon" and wanted to place them in a string somwhere I could use:

"this is {} and this is {}".format(x, y)

the value of x would be inserted where the first {} is and the value of y inserted into the next one to create a string that said 'this is py and this is thon"

so if we want to insert the value of estimate into the string we could use

age = 13
days = (age*52*7)
estimate = round(days)
#value of estimate is inserted where {} is
summary = "I am {} days old!".format(estimate)

you can read more about the format method in the documentation