How many codes containing 3 letters can be formed with the 9 letters of English alphabet if repetition is not allowed?

How many 5 - letter words can be formed out of the letters of the word KNIFE ,if repetition of letters is not allowed.

How many words can be formed using all the letters of the word HEXAGON if repetition is not allowed?

How many 4-letter code can be formed using the first 10 letters of the English alphabet, if no letter can be repeated?

How many 4-letter code can be formed using the first 10 letters of the English alphabet, if no letter can be repeated?

How many 4 -letter code can be formed using the first 10 letters of the English alphabet,if no letter can be repeated?

How many 4-letter code can be formed using the first 10 letters of the English alphabet, if no letter can be repeated?

How many 4 - letter codes can be formed using the first 10 letters of the English alphabet, if no letter can be repeated?