13/10-5/6+7/10+1/6
=(13/10+7/10)-(5/6-1/6) 交换 结合
=2-4/6
=4/3
13/10-5/6+7/10+1/6
=13/10+7/10-5/6+1/6
=2-(5/6-1/6)
=2-2/3
=1又1/3
13/10-5/6+7/10+1/6
=(13/10+7/10)-(5/6-1/6)
=2-2/3
=4/3
13/10-5/6+7/10+1/6
=13/10+7/10-5/6-1/6+2/6
=(13/10+7/10)-(5/6+1/6)+1/3
=2-1+1/3
=1+1/3
=4/3
13/10-5/6+7/10+1/6
=(13/10+7/10)-(5/6-1/6)
=20/10 -4/6
=2-2/3
=4/3