题目内容：

    It can be tough to pull kids away from their computers and mobile devices these days. While they' re playing games, wouldn't it be great if they could be learning at the same time? Good educational apps offer fun challenges that teach specific grade - level skills. Here are four that combine fun and learning.

Understanding Math ( $ 3.99 ； iOS)

Understanding Math goes beyond basic comprehension to gain a deeper understanding of the whys and hows of math. The app tracks your child's progress to determine strengths and weaknesses in different skill areas, and you can customize (订制) your child's learning experience to suit the needs.

Word Creativity Kit ( $2.99； iOS)

Word Creativity Kit aims not only to make creative writing fun but also build up grammar rules. The app presents a series of words from seven categories, such as space or fantasy. Kids add their own words to finish the complete thoughts that these words have inspired.

Barefoot World Atlas ( $4.99； iOS)

Barefoot World Atlas helps kids learn about geography and world cultures with a touch of the screen. Each region features a set of sub - topics, from wildlife and natural features to native people ,landmarks, and architecture. These facts and illustrations are delivered in photographs, sounds, and hundreds of mini videos.

My Grades & Homework ( $0.99； iOS)

A combination of grades and homework tracker, My Grades & Homework can help your child stay organized and on top of the progress in school. A convenient calendar and course list format and offer a glance at your child' s assignment schedule that he or she might not normally get from standard homework planners.

1.Which app is beneficial to children's writing skills?

A.Understanding Math. B.Word Creativity Kit.

C.Barefoot World Atlas. D.My Grades Homework.

2.What is the common part of the four apps?

A.They need purchasing when downloaded.

B.They help children improve their grades.

C.They make studies fun because of mini videos.

D.They inform parents of their children's progress.

3.What is the purpose of the text?

A.To wish readers to bing in more similar apps for children.

B.To encourage parents to allow their students to play apps.

C.To design the educational apps to combine fun and learning.

D.To introduce four educational apps for readers to buy and use.