Can anyone tell me how to be good at pre-algebra and algebra 1

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year.how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class