Secondary School (English Medium) (5 to 8) कक्षा ८ - CBSE Question Bank Solutions for Mathematics

`(125 xx x^-3)/(5^-3 xx 25 xx x^-6)`

`(16 xx 10^2 xx 64)/(2^4 xx 4^2)`

If `(5^m xx 5^3 xx 5^-2)/5^-5 = 5^12`, find m.

A new born bear weighs 4 kg. How many kilograms might a five year old bear weigh if its weight increases by the power of 2 in 5 years?

The cells of a bacteria double in every 30 minutes. A scientist begins with a single cell. How many cells will be there after 12 hours?

The cells of a bacteria double in every 30 minutes. A scientist begins with a single cell. How many cells will be there after 24 hours?

Planet A is at a distance of 9.35 × 10⁶ km from Earth and planet B is 6.27 × 10⁷ km from Earth. Which planet is nearer to Earth?

An insect is on the 0 point of a number line, hopping towards 1. She covers half the distance from her current location to 1 with each hop. So, she will be at `1/2` after one hop, `3/4` after two hops, and so on.

1. Make a table showing the insect’s location for the first 10 hops.
2. Where will the insect be after n hops?
3. Will the insect ever get to 1? Explain.

An insect is on the 0 point of a number line, hopping towards 1. She covers half the distance from her current location to 1 with each hop. So, she will be at `1/2` after one hop, `3/4` after two hops, and so on.

Where will the insect be after n hops?

An insect is on the 0 point of a number line, hopping towards 1. She covers half the distance from her current location to 1 with each hop. So, she will be at `1/2` after one hop, `3/4` after two hops, and so on.

Will the insect ever get to 1? Explain.

An electron’s mass is approximately 9.1093826 × 10^–31 kilograms. What is this mass in grams?

Consider a quantity of a radioactive substance. The fraction of this quantity that remains after t half-lives can be found by using the expression 3^–t. What fraction of substance remains after 7 half-lives? 

Use the properties of exponents to verify that statement is true.

`1/4 (2^n) = 2^(n - 2)`

Use the properties of exponents to verify that statement is true.

`4^(n - 1) = 1/4(4)^n`

Use the properties of exponents to verify that statement is true.

25(5^{n – 2}) = 5ⁿ

Fill in the blanks

In a repeater machine with 0 as an exponent, the base machine is applied 0 times. What do these machines do to a piece of chalk?

In a repeater machine with 0 as an exponent, the base machine is applied 0 times. What do you think the value of 6⁰ is?

What happens when 1 cm worms are sent through these hook-ups?

What happens when 1 cm worms are sent through these hook-ups?