13x13-12=?(13-2)x6=?3+13+13x4 用简便写法

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13x13-12=?(13-2)x6=?3+13+13x4 用简便写法

13x13-12
=13×(10+2+1)-12
=13×10+13×2+13-12
=130+26+1
=157
(13-2)x6
=(10+1)×6
=60+6
=66
3+13+13x4
=13×(1+4)+3
=65+3
=68