小學數學討論區

數字加減組合

1.
123456789之間插入若干個運算符號+或-,(僅使用+或-),請問有那些組合可使結果為10(答案有12組)
例如:1+2+34-5+67-89=10

2.同上,若改為123456798,則有16組,是那16組?

3.同上,若改為111111111,順序不同仍視為不同組合
例如:11+111-111-1=10 11+111-1-111=10 視為不同組合, 則共有多少種組合?

4.將123456789順序調換，僅使用三個加減運算，使其結果為10, 請至少舉出六種組合



小學

clock

The display of a digital clock is of the form MM:DD:HH:mm, that is , Month:Day:Hour:minute. The display ranges are
Month(MM)from 01 to 12
Day(DD)from 01 to 31
Hour(HH)from 01 to 23
Minute(mm)from 00 to 59
How many times in the year 2005 does the display show a palindrome?
(A palindrome is a number which is read the same forward as backward.
Examples: 12:31:13:21 and 01:02:20:10)
小學

box

A box without top cover is formed from a square carton size 34cm*34cm by cutting the four shaded areas. If the sides of each shaded square are whole number, find the largest possible volume of the box.
請加解答過程
小學

number N

The number N has the following properties:
(a)It consists of 4 digits, each digit is a number
less than 7.
(b)It is a square of a certain number.
(c)If 3 is added to each digit, the resulting number
is also a square of a number.
find N
請翻成中文
並解答
小學

頁面