相关经文
Duplex Process
“复式组合”
平方的特殊规律：第一个的平方、乘积的两倍、最后的平方
理论
Duplex method for squaring:
For 23²:
- Left: 2² = 4
- Middle: 2×2×3 = 12
- Right: 3² = 9
- Result: 4|12|9 = 529
步骤
1
Square first digit
2² = 4
2
Double the cross product
2×2×3 = 12
3
Square last digit
3² = 9
4
Combine with carries
529
示例
23²
中等1
First squared
2²=4
2
Cross doubled
2×2×3=12
3
Last squared
3²=9
4
Result
529
答案：529