Nếu câu hỏi là thế này: Có bao nhiêu số có 1 chữ số?
Thì mình xin được trả lời:
Gọi ab là số tự nhiên cần tìm
a có 9 cách chọn (từ 1 -> 9)
b có 9 cách chọn (b khác a)
Vậy có 9x9 = 81 số.
Nếu tính cả số âm nữa thì:
Gọi ab là số tự nhiên cần tìm
a có 18 cách chọn (từ -9 -> 9 bỏ 0)
b có 18 cách chọn (b khác a)
Vậy có 18x18 = 324số
How many 2 - digit even numbers are there ?
Answer: ............. number .
how many two-digit numbers are there in which the tens digit is greater than the ones digit?
how many 2-digit even numbers are there ?
Choose 3 digits, without repetition, from 1, 2, 4, 6, 8 to form 3-digit even numbers. How many numbers are there ?
Please help me !
Choose 3 digits from 8, 6, 0, 5, 2 and 1 to form 3-digit numbers. How many odd numbers
are there? (The repetition of digits is not allowed)giúp me với
The numbers from 1 to 1000 are written. How many of these numbers have at least two digit 5?
choose 3 digits from 1, 3, 4, 5, 9 to form 3-digit numbers. how many number(s) that can be divisible by 5 is / are there?
choose 3 digits from 1, 3, 4, 5, 9 to form 3-digit numbers. how many number(s) that can be divisible by 5 is / are there?
Write the words in number form which consist of: 7 hundred thousands, 6 thousands, 3 hundreds, 4 tens and 2 units.
Answer:
Câu 2:
Fill in the sequence with the missing number in order to have 3 consecutive natural numbers.
897; ; 899
Câu 3:
Fill in the sequence with the missing number in order to have 3 consecutive natural numbers.
; 87; 88
Câu 4:
How many single digit numbers are there?
Answer: numbers.
Câu 5:
6 is just after of 5 and 5 is just before of 6. What is the product of just after and just before of 10?
Answer:
Câu 6:
Jean has 3014 beads. She has 497 beads less than Gillian. How many beads do they have altogether?
Answer: They have beads altogether.
Câu 7:
There are 56 apples in a basket. of them are green and the rest are red. How many red apples are there?
Answer: There are red apples.
Câu 8:
The perimeter of a square garden is 36m. What is its area?
Answer: Its area is .
Câu 9:
248 boys and 418 girls were divided into groups of 9. How many groups were there altogether?
Answer: groups.
Câu 10:
Mr Junior bought 1 magazine, 1 book and 1 pen. The pen costs 5 dollar, the book costs 31 dollar more than the pen. The magazine costs twice as much as the book. How much did he spend on the three things?
Answer: He spent dollar.
