Easy Maths Brain Teasers | Algebra Problems - Free Printable

Let’s solve this step by step.

We have four boxes: A, B, C, D.

From the image, we can write these equations:

1. A + B = 13
2. C + D = 4
3. A - C = 3
4. B + D = 8

We need to find the values of A, B, C, and D that satisfy all four equations.

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Let’s start with equation (3):
A - C = 3 → So, A = C + 3

Now plug this into equation (1):
A + B = 13 → (C + 3) + B = 13 → B + C = 10 → Let’s call this equation (5)

Now look at equation (2):
C + D = 4 → So, D = 4 - C

Plug this into equation (4):
B + D = 8 → B + (4 - C) = 8 → B - C = 4 → Let’s call this equation (6)

Now we have two new equations:

(5) B + C = 10
(6) B - C = 4

Add them together:
(B + C) + (B - C) = 10 + 4 → 2B = 14 → B = 7

Now plug B = 7 into equation (5):
7 + C = 10 → C = 3

Now use C = 3 in equation (3):
A = C + 3 = 3 + 3 = 6

Use C = 3 in equation (2):
D = 4 - C = 4 - 3 = 1

Check all equations:

- A + B = 6 + 7 = 13 ✔
- C + D = 3 + 1 = 4 ✔
- A - C = 6 - 3 = 3 ✔
- B + D = 7 + 1 = 8 ✔

All check out!

Final Answer:
A = 6, B = 7, C = 3, D = 1