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

m (Solution)
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-edited by De-math-wiz
 
-edited by De-math-wiz
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== Solution ==
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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
  
 
879 x 492 = 432,468
 
879 x 492 = 432,468
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     879
 
     879
 
x    492
 
x    492
________
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   1,758
 
   1,758
   79,1100
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   79,110
+351,6000
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+351,600
_________
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=432,468  
432,468 therefore add 1+9+1+2 = 13
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 +
Therefore add 1+9+1+2 = 13
 
The Answer is (A) 13
 
The Answer is (A) 13

Revision as of 16:10, 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

879 x 492 = 432,468

    879

x 492

  1,758
 79,110

+351,600 =432,468

Therefore add 1+9+1+2 = 13 The Answer is (A) 13