Hiii, in that particualr level you have an option to strike the three 7 blocks to a lower number by pressing "S". For example on the third 7 block you press "S" three times so it becomes a 4 then after the countdown, wall of 6 will vanish and you can jump on to cross it. And if you follow this link - Strik down to the game page, you will find the gif demonstrating it.
Thank you so much for playing the game and sorry that you have to try so many times, hope that now you will enjoy it more!