Răspuns:
84 : 4 : a = 3
21 : a = 3
a = 21 : 3
a = 7
a - 123 : 3 = 9
a - 41 = 9
a = 9 + 41
a = 50
154 : 7 × a = 44
22 × a = 44
a = 44 : 22
a = 2
a + 396 : 9 = 100
a + 44 = 100
a = 100 - 44
a = 56
a × 196 : 4 = 0
a × 49 = 0
a = 0 : 49
a = 0
555 : 5 - a = 100
111 - a = 100
a = 111 - 100
a = 11
a - 749 : 7 = 93
a - 107 = 93
a = 93 + 107
a = 200
965 : 5 + a = 500
193 + a = 500
a = 500 - 193
a = 307
270 : 5 : a = 9
54 : a = 9
a = 54 : 9
a = 6
129 : 3 × a = 86
43 × a = 86
a = 86 : 43
a = 2
810 : 9 + a = 100
90 + a = 100
a = 100 - 90
a = 10
200 : 4 × a = 50
50 × a = 50
a = 50 : 50
a = 1