640 US customary teaspoons in metric teaspoons

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

We know (by definition) that: $1\mathrm{usteaspoon}\approx 0.98578431875\mathrm{brteaspoon}$

We can set up a proportion to solve for the number of metric teaspoons.

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

Conclusion: 640 ⁢ usteaspoon ≈ 630.901964 ⁢ brteaspoon

Conversion in the opposite direction

The inverse of the conversion factor is that 1 metric teaspoon is equal to 0.00158503231414889 times 640 US customary teaspoons.

It can also be expressed as: 640 US customary teaspoons is equal to $\frac{1}{\mathrm{0.00158503231414889}}$ metric teaspoons.

Approximation

An approximate numerical result would be: six hundred and forty US customary teaspoons is about six hundred and thirty point eight nine metric teaspoons, or alternatively, a metric teaspoon is about zero times six hundred and forty US customary teaspoons.