Kathy counts in total 9 goats and sheep at the petting zoo. Her brother counts 4 goats. Then if you subtract the amount of goats from the total amount, then you obtain the amount of sheep.
9-4=5 is the number of sheep at the petting zoo.
2 way (with equation)
Let x be the number of sheep at the petting zoo. If brother counts 4 goats, then the total number of animals is x+4. Kathy counts in total 9 goats and sheep at the petting zoo, then x+4=9.
Solve this equation:
x+4-4=9-4,
x=5.
3 way (with equation)
Let x be the number of sheep at the petting zoo. If total number of animals is 9, then the amount of goats can be found as 9-x. Brother counts 4 goats, then
