(4 ) 2 (4 ) 2 = 4 × 4 → 4 × 4 × × 2 = 4 × 2 = 16 2 2 3 (2 ) 2 2 2 3 (2 ) = 2 × 2 × 2 2 = 2 1×3 × 1×3 × 2×3 = 2 ( − 1) 2 2 ( − 1) 2 = × − − 2 = − − 2 = −