How to convert 405 metric teaspoons to US customary teaspoons?
We know (by definition) that:
We can set up a proportion to solve for the number of US customary teaspoons.
Now, we cross multiply to solve for our unknown :
Conversion in the opposite direction
The inverse of the conversion factor is that 1 US customary teaspoon is equal to 0.00243403535493827 times 405 metric teaspoons.
It can also be expressed as: 405 metric teaspoons is equal to US customary teaspoons.
An approximate numerical result would be: four hundred and five metric teaspoons is about four hundred and ten point eight three US customary teaspoons, or alternatively, a US customary teaspoon is about zero times four hundred and five metric teaspoons.
 The precision is 15 significant digits (fourteen digits to the right of the decimal point).Results may contain small errors due to the use of floating point arithmetic.