用简便方法计算：①2013²②1.234²+0.766²+2.468×0.766

用简便方法计算：①2013²②1.234²+0.766²+2.468×0.766
用简便方法计算：①2013²②1.234²+0.766²+2.468×0.766

用简便方法计算：①2013²②1.234²+0.766²+2.468×0.766
2013"
= 2013" - 13" + 13" - 3" + 3"
= ( 2013 - 13 )( 2013 + 13 ) + ( 13 - 3 )( 13 + 3 ) + 9
= 2000 X 2026 + 10 X 16 + 9
= 4052 000 + 160 + 9
= 4052 169
计算平方,用平方差的算法更轻松
1.234" + 0.766" + 2.468 X 0.766
= 1.234" + 2 X 1.234 X 0.766 + 1.234 X 0.766 + 0.766"
= ( 1.234 + 0.766 )"
= 2"
= 4