7分之6-（10分之3-7分之1）+10分之7
=6/7-3/10+1/7+7/10
=(6/7+1/7)+7/10-3/10
=1+7/10-3/10
=14/10
（2分之1+12分之5×3分之2）÷9分之7
=(1/2+5/18)x9/7
=1/2x9/7+5/18x9/7
=9/14+5/14
=1
0.36×6分之5+6分之5×0.64
=5/6x(0.36+0.64)
=5/6x1
=5/6
6分之5x+6分之1=9分之8
5x/6=8/9-1/6
5x/6=13/18
x=13/15
0.69+0.53+2.47+0.31
=(0.69+0.31)+(0.53+2.47)
=1+3
=4