Prima soluzione: 20 ⋅ 5

(5 + 5 + 5 + 5) ⋅ 5 = 100

Seconda soluzione: 25 ⋅ 4

(5 ⋅ 5) ⋅ (5 - 5 : 5) = 100

Terza soluzione: 125 - 25

(5 ⋅ 5 ⋅ 5 ⋅ 5) - 5 ⋅ 5 = 100