The square of the number 217 can be expressed as 47098.

It can be written that 217 = 200 + 17

∴ 217² = (200+ 17)² = 200 × (200 + 17) + 17 × (200 + 17)

            = 200² + 200 × 17 + 17 × 200 + 17²

            = 40000 + 3400 + 3400 + 289

Thus, the square of the number 217 can be expressed as

217² = 40000 + 3400 + 3400 + 289

This method helps in finding the square of the number 217 without actually multiplying the numbers.

217² = 40000 + 3400 + 3400 + 289

∴ 217²  = 47089