Difference between revisions of "1998 CEMC Gauss (Grade 7) Problems/Problem 6"

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While doing the long multiplication the numbers in the thousand place are 1, 9, and 2 respectively. When added the sum is 13, so the answer is (A) 13
 
While doing the long multiplication the numbers in the thousand place are 1, 9, and 2 respectively. When added the sum is 13, so the answer is (A) 13
  
879 x 492 = 432,468
+
879x492 = 432,468
  
 
     879
 
     879
x   492
+
  x 492
  
 
   1,758
 
   1,758
 
   79,110
 
   79,110
 
+351,600
 
+351,600
 +
 
=432,468  
 
=432,468  
  
Therefore add 1+9+1+2 = 13
+
Therefore add 1+9+1+2 = 13, so (A) 13 is correct answer.
The Answer is (A) 13
 

Revision as of 16:13, 12 May 2024

Problem

In the multiplication question, the sum of the digits in the four boxes is:

[Multiply $879 \times 492$ using long multiplication. Find the sum of the four numbers in the thousands place column.]

$\text{(A)}\ 13 \qquad \text{(B)}\ 12 \qquad \text{(C)}\ 27 \qquad \text{(D)}\ 9 \qquad \text{(E)}\ 22$

Solution

Multiplying, we find that the numbers in the thousands place column are 1, 9, 1, and 2 respectively. Adding yields a sum of 12, so the answer is $\text{(B)}.$

-edited by coolmath34

If anyone knows the LaTeX to show long multiplication, any help would be appreciated.

-edited by De-math-wiz

Solution

While doing the long multiplication the numbers in the thousand place are 1, 9, and 2 respectively. When added the sum is 13, so the answer is (A) 13

879x492 = 432,468

    879
  x 492
  1,758
 79,110

+351,600

=432,468

Therefore add 1+9+1+2 = 13, so (A) 13 is correct answer.