Sharing your mathematics in MathYouLike

Tuan's parents registered their marriage at Ward People's Committee with certificate No. 123.

After 5 years of marriage, birth parents Tuan sister. On Tuan's sister 21-year-old's birthday, Tuan said: "By 2019, Father's age will be twice the sum of the numbers in his father's birthday."

Asked Tuan's father in what year?

Long has some green and red balls. Red number is red
1/5 green balls. Then Long for Minh 3 green balls and buy a red ball full of red ball now equal

1/3 green balls.

Calculate the initial number of marbles of Long.

How many numbers from 1 to 200 do not have the digit 2?

it is given a,b and c are 3 consecutive odd numbers. Also, b3 = 3375. Find the value of ac

Given three number a,b,c know :

0 $\leq$ a $\leq$ b + 1 $\leq$ c + 2 and a + b + c = 1 .

Find the smallest value of c

Give $\frac{2 a + b + c + d}{a} = \frac{a + 2 b + c + d}{b} = \frac{a + b + 2 c + d}{c} = \frac{a + b + c + 2 d}{d}$

Calculator : M = $\frac{a + b}{c + d} + \frac{b + c}{d + a} + \frac{c + d}{a + b} + \frac{a + d}{b + c}$

Given natural numbers, a and b, that sastify the expression: (a + 2016b) $⋮$ 2017. Prove that:

A = (2a + 2015b)(3a + 2014b)...(2015a + 2b) $⋮$ 20172014.

the smallest number such that the product of all it is digit is 20 is:......