640 metric teaspoons in US customary cups

Conversion formula
How to convert 640 metric teaspoons to US customary cups?

We know (by definition) that: $1\mathrm{brteaspoon}\approx 0.0211337641886519\mathrm{uscup}$

We can set up a proportion to solve for the number of US customary cups.

Now, we cross multiply to solve for our unknown $x$:

Conclusion: 640 ⁢ brteaspoon ≈ 13.525609080737215 ⁢ uscup

Conversion in the opposite direction

The inverse of the conversion factor is that 1 US customary cup is equal to 0.07393382390625 times 640 metric teaspoons.

It can also be expressed as: 640 metric teaspoons is equal to $\frac{1}{\mathrm{0.07393382390625}}$ US customary cups.

Approximation

An approximate numerical result would be: six hundred and forty metric teaspoons is about thirteen point five two US customary cups, or alternatively, a US customary cup is about zero point zero seven times six hundred and forty metric teaspoons.