每周两次，孩子们被测试基本数学技能，如加法和减法。

Twice a week the children are tested in basic mathematical skills such as ___addition and subtraction.

在会计中，数字的准确加法至关重要。

In accounting, accurate ___addition of figures is crucial.

学习加法是算术的第一步。

Learning ___addition is the first step in arithmetic.