1. ## Math puzzles questions?

1. What number should replace the question mark?

2.What number should replace the question mark?

3.What number should replace the question mark?

4.What number should replace the question mark?

5.What number should replace the question mark?

Regards,

2. ## Re: Math puzzles questions?

Hello, amrithaa!

2. What number should replace the question mark?

. . $\boxed{\begin{array}{ccccc} .&.&.&14&. \\ .&22&.&.&. \\ .&.&.&34&. \\ 41&.&.&.&. \\ .&.&53&.&? \end{array}}$

Spoiler:

Each number indicates its row and column.
The "?" is in the 5th row, 5th column.
Its number is 55.

3. What number should replace the question mark?

. . $\boxed{\begin{array}{cc}5 \\ 8\quad 5 \\ 1\quad 7 \end{array}} \qquad \boxed{\begin{array}{c} 4 \\ 7\quad 6 \\ 1\quad 9 \end{array}} \qquad \boxed{\begin{array}{c} ? \\ 9\quad 1 \\ 1\quad 3 \end{array}}$

Spoiler:

The second row divided by the third row equals the top row.

$85 \div 17 \:=\:5,\quad 76 \div 19 \:=\:4,\quad 91\div 13 \:=\:{\color{red}7}$

4. What number should replace the question mark?

$\boxed{\begin{array}{c|c|c} 47&55&63 \end{array}} \quad \boxed{\begin{array}{c|c|c}85&92&99 \end{array}} \qquad \boxed{\begin{array}{c|c|c} 73&\;?\;&25 \end{array}}$

Spoiler:

The middle number is the average of the other two.

$\frac{47+63}{2} \:=\:55,\quad \frac{85+99}{2} \:=\:92,\quad \frac{73+25}{2} \:=\:{\color{red}49}$

3. ## Re: Math puzzles questions?

Originally Posted by amrithaa
1. What number should replace the question mark?
Each row is 8 times the immediate row above. 9X8=72. 72X8=576. bottom row 576X8=4608. So there will be 0 in place of question mark in the lowest row.

4. ## Re: Math puzzles questions?

Originally Posted by amrithaa

5.What number should replace the question mark?

Each two digit number is a sum of digits of one three digit number. 2+6+8=16; 3+5+9=17; 2+6+3=11; and therefore the number in place of question mark is 5+1+6=12.

5. ## Re: Math puzzles questions?

Hello again, amrithaa!

5. What number should replace the question mark?

. . $\boxed{\begin{array}{c} 268 \qquad 11 \\ \\[-3mm] 17 \qquad\quad 259 \\ ? \\ 16 \qquad\quad 516 \\ \\[-4mm] 263 \end{array}}$

Spoiler:

Each 2-digit number is the digit-sum of a 3-digit number.

. . $\begin{array}{ccc}263 & \to & 11 \\ 268 & \to & 16 \\ 359 & \to & 17 \\ 516 & \to & {\color{red}12} \end{array}$

6. ## Re: Math puzzles questions?

Lol 4 is not as bad: the number in the middle is the average of the 2 others on the sides.

7. ## Re: Math puzzles questions?

3. 5=85/17, 4=76/19 so ?=91/13