Which numbers are missing? - Math puzzle

[@KevFrost]

You can intuitively see that A and D are identical from A+B = 7 and D+B = 7. From that you can see that C+A = 10 and C-A= 1 gives you A=D=4.5 and C=5.5

[@inyobill]

by analysis, actually, but correct.

[@mattc3581]

My immediate reaction was that if the bottom line was C+D it would have to total 10, since the total of the sums across must equal total of the sums downward. If we know that C+D=10 and C-D=1 then it is obvious that C=5.5 and D=4.5. Working out A and B takes another second or so, overall less than 10 seconds to get the 4 values. Writing out as many simultaneous equations as in the video seems massively longwinded.

[@zygoloid]

From the columns we can see that A+B+C+D = 17 From the rows we can see that A+B+C-D = 8 So 2D = 9, D = 4½. So C = 5½, A = 4½, B = 2½.

[@fuchur56bekannt92]

Thank you very much and much success for your new Channel!! 💙🐬

[@jerryeldridge1690]

I solved with sympy: "import sympy as sp"; "A,B,C,D = sp.symbols('A,B,C,D')"; "eqs = []"; "eqs.append(sp.Eq(A+B,7))";"eqs.append(sp.Eq(C-D,1))";"eqs.append(sp.Eq(A+C,10))";"eqs.append(sp.Eq(B+D,7))";"sp.solve(eqs)" results in {A: 9/2, B: 5/2, C: 11/2, D: 9/2}.

[@WombatMan64]

Def started with since a+b=7 and b+d=7, therefore a=d. Then I did similar things for the rest, but getting rid of one variable immediately made it a bit easier.

[@mugoxmugox]

Woow, this is nice

[@MathQueenSusanne]

Great, that you liked it!

[@utedalheimer1742]

Thank you so much ❤❤

[@finlandtaipan4454]

I spent a minute trying to come up with a solution with only integers. It wasn't there so I just enjoyed the show.

[@estatehelper921]

i did it with U

[@MathQueenSusanne]

Awesome! Could you follow? 😊

[@estatehelper921]

@ yes

[@ehrenwerterpelikan9156]

I first thought that all numbers had to be integers, but none of the numbers I tried worked. 😅 So I watched your video. Thank you!

[@VicVelez-tf8rd]

I first noticed from the 1st and 3rd equations that a=d, both =7-b. She subtracts the new equations and gets -2c, adding them gets you 2b=5, (then b=2.5.

[@morphilou]

if a+b = b+d ==> a = d and if a+c = 10 with also c-d = 1 and therefore c-a = 1 ==> 2a = 9 dc a =4.5 like d and after even un IQ of 80 can end ^^ a=4.5 d=4.5 b=1 c=5.5 30 sec top chrono

[@Birol731]

My way of solution ▶ A+B= 7 A+C= 10 B+D= 7 C-D= 1 ⇒ A+B= 7 -A-C= -10 ⇒ B-C= -3 C-B= 3 B+D= 7 C-B= 3 ⇒ D+C= 10 C-D= 1 ⇒ 2C= 11 C= 11/2 C= 5,5 D+C= 10 C= 5,5 ⇒ D= 4,5 B+D= 7 D= 4,5 ⇒ B= 2,5 A+B= 7 B=2,5 ⇒ A= 4,5 𝕃 = { 4,5 ; 2,5 ; 5,5 ; 4,5 }

[@panlomito]

Quite easy to see that A = D so there are 4 equations and 3 unknown and therefor really too easy to solve. Better make it a 4 by 4.

[@Sg190th]

I gave up but I knew A = D lol

[@MathQueenSusanne]

But you tried, which is great!

[@gavinausten1825]

You are just doing re runs of another channel. 2 posts in the last 5 days have already been done by him.🤨