Final answer:
To double the amount of sugar required in the recipe, Sally simply needs to multiply the original amount, 1/4 cup, by 2, which results in 1/2 cup of sugar.
Step-by-step explanation:
To double the amount of sugar in a recipe, Sally needs to multiply the original quantity by two. If the recipe calls for 1/4 of a cup of sugar, doubling it would be a simple multiplication:
1/4 cup of sugar × 2 = 1/2 cup of sugar.
Therefore, Sally would need 1/2 cup of sugar to double the amount required by her Christmas cookies recipe.