Реши устно и заполни пропуски

1. \(2780-170\implies\) [ ] \(+\,540\implies\) [ ] \(:25\implies\) [ ] \(+\,854\implies\) [ ].
2. \(1100+1500\implies\) [ ] \(:130\implies\) [ ] \(+\,55\implies\) [ ] \(\cdot\,8\implies\) [ ].
3. \(2400:160\implies\) [ ] \(\cdot\,105\implies\) [ ] \(-\,350\implies\) [ ] \(+\,785\implies\) [ ].