6.
1
68
61
2
m21 =
3
m22=
m23 -

1 = 51
2= 61
3= 29
Step-by-step explanation:
1) 61+68= 129
180-129= 51
2) 61 is across it so they have the same number
3) 61 +90= 151
180-151= 29