How blockchain.info calculate the value transacted Having this address: https://blockchain.info/address/19tqZYnP9youKtbene2FZiZtZyJYaLeBDw

The last transaction says that this address received 0.0236 BTC

But even knowing the value in and the value out I am not able to calculate that value:
https://blockchain.info/tx/831c976cb54f27e5a496db749fc9e865c8e077006225d1dfaf61d998fe5a3186

In:
---
15Rhv2dsEjFaHzMhPsjGmFxgqCRhCmggjj (0.04583825 BTC - Output)
13LwYeB93Bmo2aWqGyK1ybtF9JiupPFVey (0.029625 BTC - Output)
1BxdV34eTe1YJBJpScGx6jRRVDQBeRf5qj (0.00696224 BTC - Output)

Out:
----
1BTvKHzbfm3RjPMxDZSsG2YYuaEHgfdJNP - (Spent) 0.00045884 BTC
1NCLWFw6F2nJ2pgBWy96K37rbx7VSLZs66 - (Unspent) 0.00239111 BTC
1D7BNbWBPuL22TW6WuoSq5sRrbPAxeJw8g - (Spent) 0.0156 BTC
19tqZYnP9youKtbene2FZiZtZyJYaLeBDw - (Unspent) 0.0236 BTC
1wLbaePtYhh2t5Cgd5NF59LX6Pooe1yLH - (Spent) 0.00920259 BTC
3HXAkXTYvtLzYuudDfNZBMSoueUtvdwXAz - (Unspent) 0.03036754 BTC


What I tried is sum all the In's and then substract the Out that has been spent and the fees.

What I am doing wrong? How I can calculate 0.0236 BTC
You do not have to calculate the in/out values to see how many bitcoins have been "sent" to an address.

You see, outputs from a transaction can be "locked" to a specific address. However, the address page on blockchain.info shows all the transactions that have resulted in an output being locked to that address.

In the most recent transaction on that page, you can see that one of the outputs has been locked to that specific address:

Out:
----
1BTvKHzbfm3RjPMxDZSsG2YYuaEHgfdJNP - (Spent) 0.00045884 BTC
1NCLWFw6F2nJ2pgBWy96K37rbx7VSLZs66 - (Unspent) 0.00239111 BTC
1D7BNbWBPuL22TW6WuoSq5sRrbPAxeJw8g - (Spent) 0.0156 BTC
19tqZYnP9youKtbene2FZiZtZyJYaLeBDw - (Unspent) 0.0236 BTC &lt;- this one
1wLbaePtYhh2t5Cgd5NF59LX6Pooe1yLH - (Spent) 0.00920259 BTC
3HXAkXTYvtLzYuudDfNZBMSoueUtvdwXAz - (Unspent) 0.03036754 BTC


So that's where they are showing that 0.0236 has been received by 19tqZYnP9youKtbene2FZiZtZyJYaLeBDw.

I suppose showing entire transactions on an address page can be a little confusing, when it's only the outputs that are locked to an address (not entire transactions).

Here is an alternative way of viewing the balance of an address in a blockchain explorer: http://learnmeabitcoin.com/browser/address/19tqZYnP9youKtbene2FZiZtZyJYaLeBDw