1. (а+900):2 =(4+900):2=904:2=452
2. (а+900):2 = (40+900):2=940:2=470
3. (а+900):2= (а+900):2=(400+900):2=1300:2=650
4. (а+900):2 = (4000+900):2 =49000:2=24500
5. (а+900):2 = (40000+900):2 =40900:2=20450
1. (а+900):2 =(4+900):2=904:2=452
2. (а+900):2 = (40+900):2=940:2=470
3. (а+900):2= (а+900):2=(400+900):2=1300:2=650
4. (а+900):2 = (4000+900):2 =49000:2=24500
5. (а+900):2 = (40000+900):2 =40900:2=20450