Answer:
first one minus 12 each time
second one add 2/4 each time
third one add the answer by it self
forth one it's add 0.4 each time
Step-by-step explanation:
1. 52-12=40 40-12=28 so -12
2. 3/4-1/4= 2/4 so 2/4
3. 2+2=4 4+4=8
4. 1.5-1.1=0.4
