Question

445:(1225-415)+1516*415

Answer 1

4/45 : (12/25 - 4/15) + 15/16 * 4/15 = 2/3

1) 12/25 - 4/15 = 36/75 - 20/75 = 16/75
2) 4/45 : 16/75 = 4/45 * 75/16 = (1*5)(3*4) = 5/12
3) 15/16 * 4/15 = 4/16 = 1/4
4) 5/12 + 1/4 = 5/12 + 3/12 = 8/12 = 2/3

Пояснения:
12/25 = (12*3)/(25*3) = 36/75 - доп.множ.3
4/15 = (4*5)/(15*5) = 20/75 - доп.множ. 5
4/16 = (4:4)/(16:4) = 1/4 - сократили на 4
1/4 = (1*3)/(4*3) = 3/12 - доп.множ. 3
8/12 = (8:4)/(12:4) = 2/3 - сократили на 4

Answer 2

спасибо