Difference in the production of food-grains between 1991 and 1994 = Production of food-grains in 1991 - Production of food-grains in 1994
Put the value by seeing the graph
Difference in the production of food-grains between 1991 and 1994 = ( 60 − 50 ) x 1000 = 10 x 1000 = 10,000