Subtraction with Eggs app provide the simplest way to learn subtraction by regrouping,it can help kids to know how to borrow in subtraction , this app use hatch out birds to help kids understand subtraction and this app dynamic to generate subtraction's questions, so you can get a lot of practice questions.

There is also an no in-purchase app :
https://itunes.apple.com/us/app/subtractions-with-eggs-for-school/id838762880

There are 3 functions in this app:
Function 1-> Subtract one-digit numbers - up to 10
Function 2->Subtract two-digit numbers - with regrouping
Function 3->Subtraction practices game (Play it,tilt to move left or right.)

You can download this app free to use Function 1 and Function 3, if you like this app and want to try function 2 ,you can unlock it on parents page.

The function 2 can help kids learn subtraction with regrouping more easy.
For example: 82-27 =?
you can follow the steps to do subtraction by regrouping:
1. 2 is less than 7, so we need to regroup 1 ten as 10 ones, drag 1 ten to ones’ box.
2. After regroup, there are 7 tens and 12 ones.
3. Click 7 eggs to hatch out 7 birds
4. Click 2 tens eggs to hatch out 20 birds
5. Check the remaining number of eggs, click the right answer's button

It has 3 levels in the function 2,you can click the star button to switch levels:
1 star level : subtraction that don't need regrouping
2 stars level: 2 digits minus 1 digit and need regrouping
3 stars level: 2 digits minus 2 digits and need regrouping

If you are interested in this app, you can watch the following video:
https://www.youtube.com/watch?v=2MVMSE1kIyk

Note for Parents
This app:
- Contains a limited amount of free content with an in-app purchase to unlock all items in the Parents page.
- Does contain links to developer's other apps on a separate "Parents" page.

As a MOMs with Apps member,we follow the "Know What's inside" best practices for kids' apps.
http://momswithapps.com/