Definition df-4

Description: Define the number 4. (Contributed by NM, 27-May-1999)

	Ref	Expression
Assertion	df-4	$$⊢4=3+1$$

Detailed syntax breakdown

Step	Hyp	Ref	Expression
0		c4	$$class4$$
1		c3	$$class3$$
2		caddc	$$class+$$
3		c1	$$class1$$
4	1 3 2	co	$$class\left(3+1\right)$$
5	0 4	wceq	$$wff4=3+1$$