Help if you can, it's beaten me!

Table a
game 1 01:23 01:57
game 2 02:34 02:56
game 3 03:04 03:34

Table b
block 1 01:23 01:34
block 2 01:44 01:52
block 3 01:56 02:45
block 4 02:50 03:34

I want a formula for many minutes a game has been played within a block. Eg. game 1 is
block 1 - 11mins
block 2 - 8 mins
block 3 - 1 min
=20 mins in total.

I have been trying all kinds of formulas and can't figure it out. I want to be able to calculate total minutes for game 1, game 2, & game 3 from the times within the blocks.

Help appreciated

Thanks..