Theorem add42i 8245

Description: Rearrangement of 4 terms in a sum. (Contributed by NM, 22-Aug-1999.)

Hypotheses

Ref	Expression
add.1	⊢ 𝐴 ∈ ℂ
add.2	⊢ 𝐵 ∈ ℂ
add.3	⊢ 𝐶 ∈ ℂ
add4.4	⊢ 𝐷 ∈ ℂ

Assertion

Ref	Expression
add42i	⊢ ((𝐴 + 𝐵) + (𝐶 + 𝐷)) = ((𝐴 + 𝐶) + (𝐷 + 𝐵))

Proof of Theorem add42i

Step	Hyp	Ref	Expression
1		add.1	. . 3 ⊢ 𝐴 ∈ ℂ
2		add.2	. . 3 ⊢ 𝐵 ∈ ℂ
3		add.3	. . 3 ⊢ 𝐶 ∈ ℂ
4		add4.4	. . 3 ⊢ 𝐷 ∈ ℂ
5	1, 2, 3, 4	add4i 8244	. 2 ⊢ ((𝐴 + 𝐵) + (𝐶 + 𝐷)) = ((𝐴 + 𝐶) + (𝐵 + 𝐷))
6	2, 4	addcomi 8223	. . 3 ⊢ (𝐵 + 𝐷) = (𝐷 + 𝐵)
7	6	oveq2i 5962	. 2 ⊢ ((𝐴 + 𝐶) + (𝐵 + 𝐷)) = ((𝐴 + 𝐶) + (𝐷 + 𝐵))
8	5, 7	eqtri 2227	1 ⊢ ((𝐴 + 𝐵) + (𝐶 + 𝐷)) = ((𝐴 + 𝐶) + (𝐷 + 𝐵))

Syntax hints:   = wceq 1373   ∈ wcel 2177  (class class class)co 5951  ℂcc 7930   + caddc 7935

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 711  ax-5 1471  ax-7 1472  ax-gen 1473  ax-ie1 1517  ax-ie2 1518  ax-8 1528  ax-10 1529  ax-11 1530  ax-i12 1531  ax-bndl 1533  ax-4 1534  ax-17 1550  ax-i9 1554  ax-ial 1558  ax-i5r 1559  ax-ext 2188  ax-addcl 8028  ax-addcom 8032  ax-addass 8034

This theorem depends on definitions:  df-bi 117  df-3an 983  df-tru 1376  df-nf 1485  df-sb 1787  df-clab 2193  df-cleq 2199  df-clel 2202  df-nfc 2338  df-rex 2491  df-v 2775  df-un 3171  df-sn 3640  df-pr 3641  df-op 3643  df-uni 3853  df-br 4048  df-iota 5237  df-fv 5284  df-ov 5954

This theorem is referenced by: (None)