I need help with my Study Links!!

[Mackenzie S.]

Okay, so I need some help with my Study Links 2.11 and 2.9,
So I'll post the problem but I'll need to make the squares into :!: s because I don't know how to do the squares on here. :?
Okay so here's the problem:
:!: , :!: 63 - 3,9 :!: 9 = 2,83 :!:

Help?

 

[Mackenzie S.]

//sigh\\

 

[lookagain]

Okay, so I need some help with my Study Links 2.11 and 2.9,
So I'll post the problem but I'll need to make the squares into :!: s because I don't know how to do the squares on here. :?
Okay so here's the problem:
:!: , :!: 63 - 3,9 :!: 9 = 2,83 :!:

__ , __ 6 3

- 3, 9 __ 9
------------------------------
2, 8, 3 __


The bottom right digit must be a 4, because 13 - 9 = 4. You are borrowing
from the 6, then that part becomes 5 - __ = 3, so the missing digit on the middle
line is a 2. Then the __ - 9 = 8 part, so the missing digit must be a 7. But this
means the top left digit is being borrowed from. Then, for d, a digit at the top left,

(d - 1) - 3 = 2
d - 1 - 3 = 2
d - 4 = 2
d = 6.

Then the completed numbers should be

\(\displaystyle 6, 763 - 3,929 = 2,834\)

 

[Denis]

IF your teacher wants you to use algebra, one way is to assign a variable to each missing digit, like this:

  a , b , 6 , 3
- 3 , 9 , c , 9
===============
  2 , 8 , 3 , d

You then transform each (example: 23 = 2*10 + 3):

1000a + 100b + 63 - (3900 + 10c + 9) = 2830 + d
Simplify:
1000a + 100b - 10c - d = 6676 ; so:
10(100a + 10b - c) = 6676 + d : you right away see that d = 4

So 10(100a + 10b - c) = 6680
100a + 10b - c = 668
10(10a + b) = 668 + c : so c = 2

10(10a + b) = 670
10a + b = 67
10a = 67 - b : so b = 7 and a = 6

 

[soroban]

Hello, Mackenzie S!

You could have laid out the problem more clearly.
Your reference to "squares" was misleading . . . as were the commas.

Okay, so I need some help with my Study Links 2.11 and 2.9,

So here's the problem:

. . \(\displaystyle \begin{array}{ccccc} & \square & \square & 6 & 3 \\ - & 3 & 9 & \square & 9 \\ \hline & 2 & 8 & 3 & \square \end{array}\)

Are you really puzzled by what digits go in the squares?

 

[lookagain]

Hello, Mackenzie S!

You could have laid out the problem more clearly.
Your reference to "squares" was misleading . . . as were the commas.

Okay, so I need some help with my Study Links 2.11 and 2.9,

So here's the problem:

. . \(\displaystyle \begin{array}{ccccc} & \square & \square & 6 & 3 \\ - & 3 & 9 & \square & 9 \\ \hline & 2 & 8 & 3 & \square \end{array}\)

Are you really puzzled by what digits go in the squares?

If *I* were at this arithmetic level, then I would not expect to know how to solve for
the digits in the squares. I could be "puzzled."

My earlier post is wrong to have included variables and algebraic equations
in an arithmetic section.

 

[Denis]

My earlier post is wrong to have included variables and algebraic equations
in an arithmetic section.

HA! Now you've made at least 2 mistakes since kindergarden :shock:

 

[lookagain]

My earlier post is wrong to have included variables and algebraic equations
in an arithmetic section.

HA! Now you've made at least 2 mistakes since >> kindergarden << :shock:

You spelled "kindergarten" wrong!

 

[Denis]

I was thinking of posting that you spelled "kindergarten" wrong, but I decided against it.
This delete button does work, doesn't it?

I've made at least one mistake since kindergarden....now, two...