Question

(30+1)(30-1)
61*59
199*201
72*68
55^2-45^2
41^2-31^2
76^2-24^2
37^2-23^2

Answer 1

(30+1)(30-1)=30²-1²=900-1=899
61*59=3599
72*68= 4896
55^2-45^2=55²-45²=3025-2025=1000
41^2-31^2=41²-31²=1681-961=720
76^2-24^2=76²-24²=5776-576=5200
37^2-23^2=37²-23²=1369-529=840