gistfile1.txt

	$wp_customize->add_setting( 'scss-paragraph-font-size', array(
			'sanitize_callback' => 'scss_number_format',
	) );
	
	$wp_customize->add_control( 'scss-paragraph-font-size', array(
			'type'        => 'number',
			'priority'    => 10,
			'section'     => 'fonts',
			'label'       => 'Paragraph Font Size',
			'input_attrs' => array(
					'min'   => 1,
					'max'   => 100,
			),
	) );	
	
function scss_number_format($var){
	return "rem-calc(".$var.")";
}