2010 Math Challenge Grade 5 Division Orals

1. Express 3/8 as decimal [0.375]2. What fraction in lowest terms is equal to 45% [9/20]3. Write 5x 105 + 7 x 104 + 6 x 102 + 8 in standard notation. [570 608]4. Two numbers are in the ratio of 5:12. The bigger number is 108, what is the smaller?5. If a boat traveled 560 km in 8 hrs, what is its speed in kilometers per hour? [70 km/h]6. What number is 25 more than the product of 12 and 15? [205]7. What is N in 15N =225? [15]8. What is the number with a prime factorization of 23 x 32 x 5? [360]9. How many 25 centavo pieces are equal to P37.50? [150]10. Express the product of 50 000 x 60 in scientific notation. [3 x 106]11. What is the prime factorization of 240? [24 x 32 x 5]

30-second question

1. Robert mixes 3 bags of sand with 2 bags of cement. How many bags of sand should he mix with 12 bags of cement? [18]

2. Find the difference of [8 3/5 x 3] – 18 1/2. [7 3/10]3. Three loaves of bread cost P127.50; how much do 2 loaves cost? [P85]4. A machine stamps 250 envelopes in 1 2/3 minutes. How many can it stamp in 1 min? [19/4 or 4

¾]5. The product of two numbers is 15 5/6. If one number is 3 1/3, what is the other?6. The perimeter of an isosceles triangle is 53 cm. If the base is 17 cm, find the length of each leag.

[18 cm]

60-minute

1. Nine times Eva’s age