А) 659+301-(402-351)=909
1) 402-351=51
2) 659+301=960
3) 960-51=909
Б) 305-196+(286+104)=499
1) 286+104=390
2) 305-196=109
3) 109+390=499
А) 659+301-(402-351)=909
1) 402-351=51
2) 659+301=960
3) 960-51=909
Б) 305-196+(286+104)=499
1) 286+104=390
2) 305-196=109
3) 109+390=499