Explain the mistake 3/6 + 1/3= 4/9

What is the approximate total length of iron edging needed to create the square frame and the two diagonals?

Antonia and carla have an equivalant percentage of green marbles in their bags of marbles. antonia has 4 green marbles and 16 total matbles. if carla has 10 green marbles , how many total marbles does carla have

Solve this problem! extra ! 3025/5.5 = a/90.75 / = fraction