解:681减568加81等于( 194 )
∵已知需求出681减568加81等于多少
∴681减568加81
= 681 - 568 + 81
= (700 - 19)- (600 - 32)+ ( 100 - 19)
= 700 - 19 - 600 + 32 + 100 - 19
= (700 - 600 + 100)+( -19 + 32 - 19)
= ( 100 + 100)+(13 - 19)
= 200 - 6
= 194
答:681减568加81等于194
681-568+81的简便算法是:
把681分解成568+113即可。
=568+113-568+81
=113+81
=194
直接按顺序计算比较简便。
681-568+81
=113+81
=194
681-(568+81)
=681-81-568
=600-568
=32
681-568+81
=668+13-568+81
=100+13+81
=194