The old watchmaker has a special 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 ...
Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):
Showing 0 comments:
Be the first to comment!
To solve this example are needed these knowledge from mathematics:
Next similar examples:
- 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.
The rectangle is divided into seven fields. On each box is to write just one of the numbers 1, 2 and 3. Mirek argue that it can be done so that the sum of the two numbers written next to each other was always different. Zuzana (Susan) instead argue that.
The perpetrator is a number that is smaller than the number 80. It is a multiple of five and it is odd. If we added up the tens and ones of this number we get number 8.
- Roman numerals
Write numbers written in Roman numerals as decimal.
- 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?
- Addition of Roman numbers
Added together and write as decimal number: LXVII + MLXIV
- Write decimals
Write in the decimal system the short and advanced form of these numbers: a) four thousand seventy-nine b) five hundred and one thousand six hundred and ten c) nine million twenty-six
- Foot in bus
It was 102 people on the bus. 28 girls had two dogs. A 11 girls had one dog. At the next stop seceded 5 dogs (even with their owners). They got two boys together with three dogs. The bus drove one driver. How many foot were in bus?
Honza had three cages (black, silver, gold) and three animals (guinea pig, rat and puppy). There was one animal in each cage. The golden cage stood to the left of the black cage. The silver cage stood on the right of the guinea pig cage. The rat was in the
- 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 first
- Equation algebraogram
Solve the equation: oco + ivo = cita How much has the task of solutions?
- Charles Bridge
Charles Bridge was 15 times older than Frantův bridge from 1900 in 1931. How old is the Charles Bridge?
Five mates traveled and the journey they lasted 195 minutes. How long would travel only one of them?
16.2 days ..... how many hours is it?
- Unknown number 16
My number's tens is three times more then ones My number's ones is twice the number of thousands and my number's hundreds is half the number of of tens. I have two ones. which number am I?
- Turtles Žofka and Julka
Gray wolf kept in his tent turtles Žofka and Julka, which together have 200 years. After 50 years will Julka 2 times older than Žofka. How old are the turtles?
Daddy is a 46 year old and son is at age of 16. When (which year) was/will daddy 5 times more years than his son?