1)
104 × 14 = (100 + 4) × 14 = 100×14 + 4×14 = 1400 + 56 = 1456
можно и так
104 × 14 = 104 × (10 + 4) = 104×10 + 104×4 = 1040 + 416 = 1456
2)
98 x 3 = (90 + 8) × 3 = 90×3 + 8×3 = 270 + 24 = 294
можно так:
98 × 3 = (100-2) × 3 = 100×3 - 2×3 = 300 - 6 = 294