let me circle it with the same colour so you recognise that this 5 is representing 50 then finally we're in the hundreds place so 400 -100 is 300 4-1 is 3 but this 3 represents 300 this 5 represents 50 this 5 represents 5 so we're done we get 355 the farmer is left with 355 tomatoes at the end of 3 days or 300+50+5 tomatoes.