Table 6.

Hierarchical regression models predicting arithmetic ability (simple and complex subtraction) from age, gender, group, general cognitive ability, symbolic, and non-symbolic magnitude processing.

	Simple subtraction				Complex subtraction
	Step 1	Step2	Step3	Step4	Step 1	Step2	Step3	Step4
	β	β	β	β	β	β	β	β
Age (months)	0.069	0.044	−0.025	−0.044	0.258*	0.219*	0.158	0.145
Gender	−0.133	−0.129	−0.040	−0.026	−0.105	−0.090	−0.025	0.014
Group(congenital/acquired)	−0.231*	−0.151	−0.093	−0.097	−0.234*	−0.186*	−0.138	−0.163
Non-verbal IQ	—	0.137	0.068	0.054	—	0.146	0.106	0.075
Ps. (ACC)	—	0.112	0.034	0.039	—	−0.029	−0.078	−0.079
Ps. (RT)	—	−0.174	−0.052	−0.043	—	−0.151	−0.051	−0.037
Reading Com.	—	0.335*	0.322*	0.297*	—	0.174	0.164	0.123
Symbolic (ACC)	—	—	0.280*	0.241*	—	—	0.165	0.110
Symbolic (RT)	—	—	−0.246*	−0.166	—	—	−0.223*	−0.175
Non-symbolic (ACC)	—	—	—	0.222	—	—	—	0.223
Non-symbolic (RT)	—	—	—	−0.076	—	—	—	0.068
	R2 = 0.072	R2 = 0.346*	R2 = 0.443*	R2 = 0.464	R2 = 0.121*	R2 = 0.231*	R2 = 0.284*	R2 = 0.339*
	(ΔR2 = 0.273*)(ΔR2 = 0.098*)(ΔR2 = 0.021)				(ΔR2 = 0.110*)(ΔR2 = 0.053*)(ΔR2 = 0.054*)

^*p < 0.05,

Bonferroni-corrected. Ps., Processing speed; Reading Com., Reading comprehension; ACC, accuracy; RT, reaction time.