8th grade / Number / Powers & Roots / Squares and cubes / Cube roots
To calculate the cube root of a number, we need to find a number which when multiplied by itself twice (i.e., raised to the power three) gives the original number. The cube root of a number is denoted by the symbol ³√.
For example: 3 x 3 x 3 = 27 so ³√27 = 3
To calculate the cube root of a number using a calculator, we can simply enter the number and press the cube root button (³√). For example, to calculate the cube root of 64, we can enter 64 and then press the cube root button to get the answer 4. We know the answer is correct because 4 x 4 x 4 = 64. Here are some more examples:
Cube root of 8: ³√8 = 2
Cube root of 125: ³√125 = 5
Cube root of 216: ³√216 = 6
Cube root of 343: ³√343 = 7
Cube root of 512: ³√512 = 8
Cube root of 729: ³√729 = 9
Cube root of 1000: ³√1000 = 10
Most numbers do not have cube roots that are integers. Sometimes we need to find the nearest integer to the cube root of a number. For example, the cube root of 67 is approximately 4.06, so the nearest integer to the cube root of 67 is 4. Here are some more examples:
³√50 = ~3.68 which is 4 to the nearest integer
³√120 = ~4.93 which is 5 to the nearest integer
³√500 = ~7.94 which is 8 to the nearest integer
In this topic you are asked to calculate the cube root or the nearest integer to the cube root for numbers up to 1000. You will probably need a calculator when answering questions in this topic.
With our quick math tests you will be revising "Cube roots" in 2 simple steps. The math in our tests consists of 16 questions that ask you to identify the cube root or nearest integer cube root of each of the given numbers.
These math tests are designed to round off your learning experience here at Free Math Games by testing whether you can correctly recognize the math you have learned (in the multiple choice test) and that you can correctly enter the correct answers (in the writing test).
Make sure you have chosen the correct topic before starting! Although these tests are timed, try to relax and concentrate on getting the answers right at first - later you can try the tests again more quickly.
The two types of tests are:
Key features of our math tests include:
You should expect to score 8+ / 10 in each test before you select a new topic. It is a good idea to repeat the test for each topic you do after two weeks to "reinforce" the math for that topic
UXO * Duck shoot * The frog flies * Pong * Cat and mouse * The beetle and the bee
Rock fall * Four in a row * Sow grow * Choose or lose * Mix and match
This is a multiple choice activity similar to "What is it" in the Math lessons - you are shown a randomly selected question from the topic you are using. A selection of topic answers are displayed as a list. If you click/tap the speaker beside any answer you will hear the audio for that answer.
For each question, you must click on the answer that matches that question. If your answer is correct you will hear a bell and one star will be lit. The next question will be shown. If your answer is wrong, a box will open showing you what the correct answer was.
The test is timed, and the clock starts when you click the Start button. The clock stops when you click your final answer. At the end of your test a screen will tell you how many of the questions you got right and how long you took to complete the test.
The writing test checks whether you can type the correct answer using your keyboard. This test is also timed. You can do the test many times until you get a good score. To start the test, click on the "Writing test" sign in the navigation board, then click on the "Start the test" arrow.
A random problem from your selected topic is shown. Beneath the problem there is a white box into which you should type the answer. If you need a little help you can click on the "Help me" button for a tip. Only use the help if you really need to.
If you type the answer correctly your device will automatically light a star. If you have entered your answer and no star lights up, click on the tick or press Enter to check your answer. When you have tried all the questions, a screen will show you how many questions you answered correctly and how long it took.
* Try to score 8 out of 10 in both test before you choose a new topic *
* It is OK to do the tests many times if you need to *
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