# Alarm clock

The old watchmaker has a unique digital alarm in its collection that rings whenever the sum of digits of the alarm is equal to 21. Find out when the alarm clock will ring. What is their number? List all options . ..

**Correct result:****Showing 0 comments:**

Tips to related online calculators

See also our variations calculator.

Do you want to convert time units like minutes to seconds?

Would you like to compute count of combinations?

Do you want to convert time units like minutes to seconds?

Would you like to compute count of combinations?

#### You need to know the following knowledge to solve this word math problem:

## Next similar math problems:

- Hello adding

Fill letters instead of digits so the indicated sum (equal letters represent equal digits). What number is hidden under the letter J? A A H A H O A H O J -------------------------- 4 3 2 1 - Number train

The numbers 1,2,3,4,5,6,7,8 and 9 traveled by train. The train had three cars and each was carrying just three numbers. No. 1 rode in the first carriage, and in the last carriage was all odd numbers. The conductor calculated sum of the numbers in the firs - Star equation

Write digits instead of stars so that the sum of the written digits is odd and is true equality: 42 · ∗8 = 2 ∗∗∗ - Clock

What time is now, if the time elapsed after noon is 2/10 of time that elapses before midnight? - The largest number

Find the largest integer such that: 1. No figures is not repeat, 2. multiplication of every two digits is odd, 3. addition all digits is odd. - Sum of the digits

How many are two-digit natural numbers that have the sum of the digits 9? - Equation algebraogram

Solve the equation: oco + ivo = cita How much has the task of solutions? - Clubhouse

There were only chairs and table in the clubhouse. Each chair had four legs, and the table was triple. Scouts came to the clubhouse. Everyone sat on their chair, two chairs were left unoccupied, and the number of legs in the room was 101. How many chairs - Chocolate

How many times should be broken chocolate consisting of 10 × 12 pieces to get the 120 parts? - Fluid

We have vessels containing 7 liters, 5 liters and 2 liters. Largest container is filled with fluid the others empty. Can you only by pouring get 5 liters and two 1 liter of fluid? How many pouring is needed? - David number

Jana and David train the addition of the decimal numbers so that each of them will write a single number and these two numbers then add up. The last example was 11.11. David's number had the same number of digits before the decimal point, the Jane's numbe - Unknown number 24

I think the number: a - is the same as the square area that has the 12th circumfence. What is this number? b - its half is 7 times bigger than its quarter. Is this the number? - Rings - intersect

There are 15 pupils on the sporting ring. 10 pupils go to football, 8 pupils go to floorball. How many pupils go to both rings at the same time? - Seven-segmet

Lenka is amused that he punched a calculator (seven-segment display) numbers and used only digits 2 to 9. Some numbers have the property that their image in the axial or central symmetry was again give some number. Determine the maximum number of three-di - Six-digit primes

Find all six-digit prime numbers that contain each one of digits 1,2,4,5,7 and 8 just once. How many are they? - To improve

To improve her handwriting Paula practices writing the numbers 1 to 200 in words. How many times will she have written the word "one" in all? - Dd 2-digit numbers

Find all odd 2-digit natural numbers compiled from digits 1; 3; 4; 6; 8 if the digits are not repeated.