ID 935

Numbers and Arithmetic K12The first person is 100 cm tall.
Each subsequent person is 20% taller than the person before.

What will be the height of the fifth person?

ID 966

Numbers and Arithmetic K12The last digit of the number 777 is

ID 993

Numbers and Arithmetic K12Find the hundreds digit (third digit from the right) of the product:

44444 x 99999

ID 1000

Numbers and Arithmetic K12Which gives the largest answer?

ID 1880

Numbers and Arithmetic K12Which is the sum of all digits of the decimal representation of 516 x 165?

ID 2032

Numbers and Arithmetic K12The sum of the digits of a two-digit number X is Y.
The sum of the digits of X2 is Y2.
Find X.

ID 2145

Numbers and Arithmetic K12Which gives the largest answer?

ID 2225

Numbers and Arithmetic K12How many three-digit numbers have exactly five divisors including 1 and itself?

ID 2242

Numbers and Arithmetic K12Make two fractions with all the digits from 0 to 9.
Use each digit once.
They add up to exactly 1.

What is one of the fractions?

ID 3541

Numbers and Arithmetic K12What is 2 to the power of 16?

ID 3719

Numbers and Arithmetic K12If you wrote all the whole numbers from 1 through 1000, how many times would you write the digit 4?

ID 3743

Numbers and Arithmetic K12With a 1 after a nine-digit number, it is the same as a 1 before it.

Find the sum of its digits.

ID 3794

Numbers and Arithmetic K12I multiply the two page numbers and get 6006.

What is the right-hand page number?

ID 3846

Numbers and Arithmetic K12What are the two last digits of the result?
1999999991 x 2000000009

ID 4025

Numbers and Arithmetic K12If XY = 1024 and both numbers are integers, which of the following could not be a value of X nor Y?

ID 4091

Numbers and Arithmetic K12Which number is smaller than the sum of its divisors other than 1 and the number itself?

ID 4160

Numbers and Arithmetic K12Which numeral system states that

7 + 6 = 15

ID 4167

Numbers and Arithmetic K12How many digits are there in the number 62510?

Please don't use a calculator or counting apps.

ID 4378

Numbers and Arithmetic K12Which of the following gives the largest result?

Do not use a calculator.

ID 4687

Numbers and Arithmetic K12Savin's problem:

Using each of the digits 1,2,3, and 4 twice, write out an eight-digit number in which there is one digit between the ones, two digits between the twos, three digits between the threes, and four digits between the fours.
How many such numbers?

ID 4705

Numbers and Arithmetic K12What gives the smallest result?

Here we write 0.333 . . . as notation for 0.3 recurring.

ID 4786

Numbers and Arithmetic K12What is the sum of the first 100 prime numbers?

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.

ID 5001

Numbers and Arithmetic K12The average of 99 consecutive numbers is 99.
What is the average of the nine smallest of these numbers?

ID 5060

Numbers and Arithmetic K12The natural numbers are the counting numbers, like 1, 2, 3, et cetera.

An even number is a natural number which is "evenly divisible" by two.

An odd number is a natural number which is not a multiple of two.

Which statement is correct?

ID 5061

Numbers and Arithmetic K120.999 . . . means infinitely repeating decimals.

What is the largest result?

ID 5140

Numbers and Arithmetic K12A magic square is an arrangement of integers, in a square grid, where the numbers in each row, and in each column, and the numbers in the diagonals, all add up to the same number.

Place numbers 13, 14, 15, and 16 in the square to make a magic square.

Which number do you place in the top left cell?

ID 5222

Numbers and Arithmetic K12Leslie Green asks:

What is the next number in the sequence?

0, 3, 1, 4, 2

(NOTE: It is a single sequence and not two sequences interleaved.)