They devised a written mathematical system to record crop yields and the size of the population, and to assist in trade.
1	They	they	PRON	PRP	Case=Nom|Number=Plur|Person=3|PronType=Prs	2	nsubj	2:nsubj	Discourse=elaboration-additional:132->130:2|Entity=(171-person-giv:act-cf1*-1-ana-Maya_peoples)
2	devised	devise	VERB	VBD	Mood=Ind|Number=Plur|Person=3|Tense=Past|VerbForm=Fin	0	root	0:root	_
3	a	a	DET	DT	Definite=Ind|PronType=Art	6	det	6:det	Entity=(239-abstract-new-cf2-4-sgl
4	written	write	VERB	VBN	Tense=Past|VerbForm=Part	6	amod	6:amod	_
5	mathematical	mathematical	ADJ	JJ	Degree=Pos	6	amod	6:amod	_
6	system	system	NOUN	NN	Number=Sing	2	obj	2:obj	Entity=239)
7	to	to	PART	TO	_	8	mark	8:mark	Discourse=purpose-goal:133->132:0
8	record	record	VERB	VB	VerbForm=Inf	2	advcl	2:advcl:to	_
9	crop	crop	NOUN	NN	Number=Sing	10	compound	10:compound	Entity=(240-abstract-new-cf3-2-sgl(241-plant-new-cf7-1-sgl)
10	yields	yield	NOUN	NNS	Number=Plur	8	obj	8:obj	Entity=240)
11	and	and	CCONJ	CC	_	13	cc	13:cc	_
12	the	the	DET	DT	Definite=Def|PronType=Art	13	det	13:det	Entity=(242-abstract-new-cf5-2-sgl
13	size	size	NOUN	NN	Number=Sing	10	conj	8:obj|10:conj:and	_
14	of	of	ADP	IN	_	16	case	16:case	_
15	the	the	DET	DT	Definite=Def|PronType=Art	16	det	16:det	Entity=(243-person-new-cf4-2-sgl
16	population	population	NOUN	NN	Number=Sing	13	nmod	13:nmod:of	Entity=243)242)|SpaceAfter=No
17	,	,	PUNCT	,	_	20	punct	20:punct	_
18	and	and	CCONJ	CC	_	20	cc	20:cc	Discourse=joint-list_m:134->133:0
19	to	to	PART	TO	_	20	mark	20:mark	_
20	assist	assist	VERB	VB	VerbForm=Inf	8	conj	2:advcl:to|8:conj:and	_
21	in	in	ADP	IN	_	22	case	22:case	_
22	trade	trade	NOUN	NN	Number=Sing	20	obl	20:obl:in	Entity=(244-abstract-new-cf6-1-coref)|SpaceAfter=No
23	.	.	PUNCT	.	_	2	punct	2:punct	_
