This question asks you to calculate 5/8 × 2/3 - 12/35 ×7/9
First, multiply 12/35 by 7/9. But before you divide, notice that you can cancel these numbers down to smaller numbers. You can rewrite this as 12/9 × 7/35 = (4×3)/(3×3)×(7)/(7×5).
You get 4/3 × 1/5 = 4/15 .
The fraction becomes 5/6 + 2/3 - 4/15. Adding 5/6 + 2/3 gives 5/6 + 2 ×2/3 ×3 = 5/6 + 4/6. We now have a common denominator, 6.
This gives 9/6. We now have 9/6 - 4/15
You can get common denominators. 9/6 × 5/5 = 45/30. 4/15 × 2/2 = 8/30. You now have 45/30 - 8/30 = 37/30 This is the answer.
You should use you calculator to work out part (b) (i) of this question. Make sure that your calculator is in degree mode. You will get 0.4487365. However, the question asks you to write the answer to 3 decimal places. The number of decimal places is equal to the number of digits to the right of the decimal point.
You should write 0.449. You add 1 to the 8 because the number to the right of 7 is equal to or greater than 5.
This part of the question asks you to write 0.00527 in standard form. When you write a number in standard form, look at the number from left to right. Write down the first non-zero digit that you see. Write the decimal point to the right of that digit. Write down the other digits to the right of the decimal point. Multiply this number by a power of 10 that will make it equal to the original number.
In this case, your answer is 5.27 × 10-3