Video: GCSE Mathematics Foundation Tier Pack 3 • Paper 2 • Question 8

GCSE Mathematics Foundation Tier Pack 3 • Paper 2 • Question 8

03:11

Video Transcript

Part a) Find the value of the cube root of 328.509. Part b) Find the value of 7.3 minus 4.65 all squared plus the square root of 1.69.

In order to answer these questions, we’ll need to use a scientific calculator. The cube root button on the calculator looks like this and is often found above the square root button. This means that you’ll have to press shift and then the square root button.

Typing the cube root of 328.509 into our calculator gives us 69 over 10, or sixty-nine tenths. If we then press the SD button on our calculator, it turns our answer into a decimal. In this case, 69 divided by 10 is equal to 6.9. This means that the cube root of 328.509 is equal to 6.9.

We could check this answer by typing 6.9 cubed into our calculator, as the opposite of cube-rooting is cubing. 6.9 cubed is equal to 328.509. Therefore, our answer is correct.

The second part of our question can also be done by typing the whole calculation in one go into our scientific calculator. An alternative method would be to work it out one step at a time using our order of operations, also sometimes known as BIDMAS.

As 7.3 minus 4.65 is inside a bracket, we’ll work this out first. 7.3 minus 4.65 is equal to 2.65. This leaves us with a calculation 2.65 squared plus the square root of 1.69. Squaring and square-rooting both relate to indices or powers. Therefore, we can calculate these two parts at the same time. 2.65 squared is equal to 7.0225, and the square root of 1.69 is equal to 1.3.

There are no division or multiplication signs in our calculation. However, there is an addition sign, so our final step is to add 7.0225 and 1.3. This gives us a final answer of 8.3225. 7.3 minus 4.65 all squared plus the square root of 1.69 is equal to 8.3225.

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