GridlocQ

Like arithmetic puzzles? GridlocQ is a drag 'n' drop arithmetic puzzle which is suitable for all levels of ability, from beginners to geniuses.
You choose the grid size that you feel comfortable with, or just start with a simple 2x2 grid of equations and work your way up to larger and more complex puzzles as you get more confident.
All you need to do is drag the numbers from the bottom coloured panels into the grid, making sure you put them into the column of the same colour.
The app shows you the result you need to get for each row and column equation, but you need to put the numbers in the correct cells in the grid to solve the puzzle. Some puzzles have more than one solution, and the app will accept any of those solutions.
The maximum grid size depends on the size of your device, with tablets allowing grid sizes up to 9 rows and 9 columns.
All the moves you make are saved automatically and you can see how many moves you've made for each puzzle by looking at the counter in the title panel.
Choose which operators you want to use - Addition, Subtraction, Multiplication, Division and Brackets.
See a list of the puzzles you are working on.
See a list of all grid sizes and your progress with each size.
There are 25 different puzzles for each grid size and operator combination, apart from 5x5 grids which have 30 variations, with a total of up to 8000 grids being available on tablets.
Want to do the most complex puzzles? There are some puzzles for each grid size and operator combination which don't show you which columns the numbers go in. No clues at all. Good luck with them.
Here's a tip - keep in mind operator precedence when you are doing grids with multiplication, division and brackets.

Actions:
Drag numbers into the grid.
Drag numbers from one grid cell to another.
Drag numbers out of the grid.
Double tap a number in the grid to lock it in place. The colour will change to indicate it is locked. Double tap again to unlock. You can't move a number, or replace it with another number, while it's locked.

Enjoy GridlocQ!