Express 0.00078456 in scientific notation

Two factors of 28 add up to 9 what are they?

If a+b+c=8, b+c=9, c+a=11 then what is the average of a, b and c.

Tina buys 5 pounds of potatoes for $4.35 and 3 pounds of carrots for $3.57. How much does one pound of potatoes cost?

20/60 simplifies to what number

In a huge chess tournament, 45 matches were played. Find out how many people were involved if it is known that each participant played one game with every other participant in the tournament.

A newspaper reporter wants to know how popular the hobby of bird watching is in the city. He asked people at the local bird refuge if they watched birds as a hobby. Which of the following best explains whether the reporters data is valid or not?

I am very confused on how to figure out if y = 3/4x is proportional?

Alison wants to buy a mountain bike for $339.12. If she saves $28.26 each month, in how many months will she be able to buy the bike?

At 12 o'clock the temperature was 7°C. The temperature decreased by - 20°C. What is the new temperature?

Ashleys rentals charges $27.50 per hour to rent a surfboard and a wetsuit. Darlas surf shop charges $23.25 per hour to rent a surfboard plus $17 extra for a wetsuit.