1, let the original number of blocks be x, then 7/ 10X+340=9/8X will get X=800, so we use 800*3/ 10 = 240.

2. Assuming that X workers process tables, 10X*2=(56-X)* 15 gives X=24, then there should be 24 workers processing tables and 56-24 = 32 workers processing chairs.

3. Assuming that football costs X yuan, then 6X+(4 10-3X)/2 =520 gives X=70, then football needs 70 yuan and basketball needs (4 10-3*70)/4 =50 yuan. The second method can set the volleyball money as X to calculate, and try it yourself first.

4. If X field is tied, then X+3*( 14-5-X)= 19, and X=4, so we tied 4 games and won 14-5-4=5 games.