Grains of rice on a chess board

There is a story about the inventor of chess being rewarded by putting 1 grain of rice on the first square of the board; 2 on the second and so on.  How much rice does that come to?

 

The total number of grains is 1.84467440737096E+19

 

At 25mg per grain thats 461168601842739 kilogrammes of rice

 

Which in more understandable terms is:

 

461,168,601,842.739 metric tonnes

 

or


453,886,749,619.642 tons

 

That’s a lot of rice

 

If you want to play around with the numbers the calculations are:

 

[double]$result = 0

1..64 |
foreach {
 
$square = [math]::Pow(2, ($psitem -1))
$result += $square

}

$wt = 0.025

$totalweight = ($wt * $result)/1000
$totalweight

$mtwt = $totalweight /1000
$mtwt

$tons = $totalweight * 0.00098421
$tons

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