# Thread: Help, this is hard!

1. ## Help, this is hard!

1) 2 dp's
2) 3 sig figures

0.5 x 8.32 x 10^-31 x (1.84x10^5)^2 x 10^20

2. Type your entire sum into a calculator and press equals.

1. Write out that answer with just two numbers after the decimal point e.g. 52387.6680923 would be written as 52, 387.67 as the third number is rounded up or down.

2. Round your number to the nearest 100. 52387.6680923 to the nearest hundred is 524 hundred, also known as 52400.

3. Originally Posted by isuckatmaths

1) 2 dp's
2) 3 sig figures

0.5 x 8.32 x 10^-31 x (1.84x10^5)^2 x 10^20

What Bruce said above is correct. If you need help with the sig figures. Then just look at your lowest number which is 0.5

So whatever you answer is make sure it has 2 numbers in it such as 55, 0.6, 32, etc.

Hope this helped.

4. Hi

Regarding: equation = 0.5 x 8.32 x 10^-31 x (1.84x10^5)^2 x 10^20

Take a minute & note that you can rearrange the products to make them easier to calculate, before you reach for the calculator.

(10^-31)(10^20) = 10^-11 (adding the powers)

Also (1.84x10^5)^2 = (1.84^2)(10^10)

So the powers of 10 become (10^-11)(10^10) i.e. 0.1.

=> equation = 0.5 x 8.32 x (1.84^2) x 0.1
= (1.84^2) x 0.5 x 0.832, which is easier, yes?

On your calculator it's easier to do the squaring first.