Ma’ruzalar matni

42 - 5 ni hisoblash usulini toping	42 – 5 = 42 – 2 – 3 = (42 – 2) – 3 = 40 – 3 = 37;	42 – 5 = 40 + 2 – 3 = (42 + 2) – 3 = 44 – 3 = 37;	42 – 5 = 40 – 2 + 3 = (42 – 2) + 3 = 40 + 3 = 37;
42 – 5 = 40 – 2 – 3 = (42 – 2) – 3 = - 40 – 3 = 37;
38 + 5 ni hisoblash usulini toping.	38 + 5 = 38 - 2 - 3 = (38 + 2) - 2+1 = 40 + 1 = 43;	38 + 5 = 38 + 2 + 3 = (38 + 2) + 3 = 40 + 3 = 43	38 + 5 = 40 - 2 + 3 = (38 - 2) - 3 = 36 + 3 = 43;	38 + 5 = 38 + 2 + 3 = (38 - 2) - 3 = - 40 - 3 = 43;
30 - 7 ni hisoblash usulini toping.	30 – 7 = (30 - 10) – 7 = 20 + (10 + 7) = -20 - 13 = -33;	30 – 7 = (20 + 10) – 7 = 20 + (10 – 7) = 20 + 3 = 23;	30 – 7 = - (20 + 10) – 7 = -20 - (10 – 7) = -20 - 3 = -23;	30 – 7 = (20 + 10) + 7 = 20 - (10 – 7) = 20 - 3 = 13;