Metamath Proof Explorer


Theorem readdsub

Description: Law for addition and subtraction. (Contributed by Steven Nguyen, 28-Jan-2023)

Ref Expression
Assertion readdsub A B C A + B - C = A - C + B

Proof

Step Hyp Ref Expression
1 simp3 A B C C
2 readdcl A B A + B
3 2 3adant3 A B C A + B
4 repncan3 C A + B C + A + B - C = A + B
5 1 3 4 syl2anc A B C C + A + B - C = A + B
6 repncan3 C A C + A - C = A
7 6 ancoms A C C + A - C = A
8 7 3adant2 A B C C + A - C = A
9 8 oveq1d A B C C + A - C + B = A + B
10 1 recnd A B C C
11 rersubcl A C A - C
12 11 3adant2 A B C A - C
13 12 recnd A B C A - C
14 simp2 A B C B
15 14 recnd A B C B
16 10 13 15 addassd A B C C + A - C + B = C + A - C + B
17 5 9 16 3eqtr2d A B C C + A + B - C = C + A - C + B
18 rersubcl A + B C A + B - C
19 3 1 18 syl2anc A B C A + B - C
20 12 14 readdcld A B C A - C + B
21 readdcan A + B - C A - C + B C C + A + B - C = C + A - C + B A + B - C = A - C + B
22 19 20 1 21 syl3anc A B C C + A + B - C = C + A - C + B A + B - C = A - C + B
23 17 22 mpbid A B C A + B - C = A - C + B