Given equation: 8 * 14 * 3 * 24 * 7 = 168
Option 1) ×, ×, −, ×
By mathematical signs to sequentially replace the * signs then:
⇒ 8 × 14 × 3 - 24 × 7 = 168
⇒ 336 - 168 = 168
⇒ 168 = 168
Option 2) +, ×, −, ×
By mathematical signs to sequentially replace the * signs then:
⇒ 8 + 14 × 3 - 24 × 7 = 168
⇒ 8 + 42 - 168 = 168
⇒ 50 - 168 = 168
⇒ -118 = 168
Option 3) +, ×, −, +
By mathematical signs to sequentially replace the * signs then:
⇒ 8 + 14 × 3 - 24 + 7 = 168
⇒ 8 + 42 - 24 + 7 = 168
⇒ 57 - 24 = 168
⇒ 33 = 168
Option 4) ×, −, ×, +
By mathematical signs to sequentially replace the * signs then:
⇒ 8 × 14 - 3 × 24 + 7 = 168
⇒ 112 - 72 + 7 = 168
⇒ 119 - 72 = 168
⇒ 47 = 168
Hence, the correct answer is "×, ×, −, ×".