4d+6+2d4, d, plus, 6, plus, 2, d

Can someone me with the property questions for 12 13 and 14 plz

Ming says that 0.24 > 1/4 because 0.24= 2/4. which best explains mings error

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g