1a:
19+(3),4+(2),6+(2),18+(3) add up together to 47
--> R2C2 must be odd (R1+R2 total must be even)
--> R2C2={1/3/5/7/9} --> R1+R2 total =48/50/52/54/56
--> total of 1 row/column =24/25/26/27/28
1b:
1+(2)={01} so 2 of the values must be {0,1}
4+(2)={04/13} so 1 value must be {3/4}
24x(3)={138/146/226/234} so 1 value must be {3/6}
--> either {0,1,3} or {0,1,4,6} must be part of the values
1c:
Notice 0+1+3+8+9=21 & 0+1+4+6+9=20
--> {2} cannot be part of the values
(or max total sum of values =23/22 <24)
--> the set of 6 values must be from {0,1,3,4,5,6,7,8,9}
2a:
7-(2)={07/18} must include {0/1}
5+(3) must include {0/1} in R56C6
(or total sum =3+4+0 =7 >5)
--> R3456C6 must include both {0,1} of C6 --> R12C6<>{0,1}
2b:
7-(2)={07/18} must include {0/1}
--> 5+(3) cannot include both {0,1} in R56C6
--> min R56C6=0+3=3 --> max R6C5=5-3=2, must be {0/1}
2c:
7-(2)={07/18} must sum to 7/9
--> 18+(3),7-(2),5+(3) add up together to 30/32
Outies C6: min R16C5=30-28=2 --> R1C5<>{0,1}
3a:
19+(3): R1C2<>{0,1} (or max sum=1+8+9=18<19)
Hidden pair R1: R1C34={01}
R2C345 must include {0} of R2
Also 6+(3)<>{7,8,9} --> R2C345=4+6-0-1=9={036/045}
3b:
Hidden single R2: R2C2=1
--> total of 1 row/column =(47+1)/2 =24
Outies R1: R2C16=19+18+0+1-24=14={59/68}
3c:
R2: {7} cannot be part of the values
--> 7-(2)={18}, so 1 value must be 8
--> R2C16=14=[86] --> R2C345=9={045}
--> the set of 6 values must be {0,1,4,5,6,8}
Cracked.