Table 5.

Results of hierarchical regression analyses predicting numerical operations in kindergarten, Grade 2, and Grade 4.

		Kindergarten		Grade 2		Grade 4
Step		β	ΔR2	β	ΔR2	β	ΔR2
1.	Age	0.123	0.04	0.096	0.04	0.127	0.04
	Gender	-0.140		-0.143		-0.148
2.	Nonverbal intelligence	0.555∗∗∗	0.41∗∗∗	0.127	0.03	0.231∗	0.14∗∗
	inhibition	0.212∗		0.124		0.240∗
	Working memory	0.045		-0.098		0.157
3.	Number line estimation	-0.054	0.04∗	-0.065	0.01	-0.203∗	0.04
	Dot estimation	0.192∗		0.093		-0.055
Total R2			0.49∗∗∗		0.08		0.22∗∗

^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001.