# Sorting numbers and multiply each numbers

Hello,
I'm very new in MIT apps inventor.I still don't understands few blocks and how to use them.So,I have a question.Can anyone tell me how to make an instruction on how to calculate each digit of a number and can you show me have to do it .I want to make the apps to multiply each digits by a number wanted by the users and sum all of it.For example, if the user enters "2351" and multiply by "2" it will be "2×2+3×2+5×2+1×2=(4)+(6)+(10)+(2)=22".Thank you for reading this:)

You can make things easier for you if you save your multiplication until after you sum the digits,
since multiplication is distributive.

``````2*2 + 3*2 + 5*2 + 1*2 = 22 = (2+3+5+1) * 2
``````

To get a list of digits, split the number at '' (empty string) using the text split block.
You will need to remove item 1, a leftover empty string.

``````set sum = 0
for each item in the list
set sum = sum + item
(end for each)
set sum = sum * your multiplier number (2?)``````
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Do what @ABG suggests:

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Thank you vm.I will try and ask again if I dont understand anything.

TQ i will try it first:)

Im really sorry.But I forgot to add that After the user enter the numbers(2351).I wont just multiply by "2". But it will also be powered by its index.For example "(2×2^1)+(3×2^2)+(5×2^3)+(1×2^4)" Is it possible to do it?

yes it is
use additionally a counter variable and increments its value inside the for each in list loop
the power block you can find here MIT App Inventor Math Blocks

please try something and if you get stuck, post a screenshot of your relevant blocks

Taifun

Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by Taifun.

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Ok tq I will try adding it

How to do the index?

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Im sorry.I will ask carefully nest time.Thank you.

Thank you for the help

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