# Interactive science 2nd vs Let's Smile 4

The clearest difference is rating: Interactive science 2nd at 5.0 against Let's Smile 4's 2.0. Let's Smile 4's advantage is iOS requirement (10.0 vs 15.1). On price, ratings volume, update cadence and ads there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Interactive science 2nd holds the better App Store score, 5.0 against 2.0. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

Interactive science 2nd ships an update every 30 months, Let's Smile 4 every 19 months. The most recent releases landed on September 28, 2026 and October 15, 2026 respectively.

## The numbers

| Metric | Interactive science 2nd | Let's Smile 4 |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/interactive-science-2nd/id1515085020/reviews)** | [2.0 (1 ratings)](https://appshunter.io/ios/app/lets-smile-4/id1566810330/reviews) |
| Number of ratings | 1 | 1 |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 30 months | **Every 19 months** |
| Monetization | Free | Free |
| Size | 17 MB | 914 MB |
| Requires iOS | 15.1 | **10.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [언어세상](https://appshunter.io/developer/939474498) | [e-future Co., Ltd.](https://appshunter.io/developer/522346678) |

## What reviewers say

### Interactive science 2nd

[App page](https://appshunter.io/ios/app/interactive-science-2nd/id1515085020)

Explore core science concepts across life, physical, earth, space, and technology. This app uses colorful visuals to make learning easier and deeper, aligning with US and Canadian national curricula.

**Highlights:** Life Science topics, Physical Science topics, Earth/Space Science topics, Technology and Society, US and Canada curriculum alignment, Visual learning aids

**Features:** macOS Compatibility

**In-app purchases:** none


### Let's Smile 4

[App page](https://appshunter.io/ios/app/lets-smile-4/id1566810330)

This app offers a seven-level primary English course for young EFL learners. It uses engaging stories, songs, and games to build confidence and motivate students. The curriculum aligns with CEFR and YLE test objectives, integrating language learning with various school subjects and global topics.

**Highlights:** Animated stories and songs, Communicative games, CLIL lessons, Vocabulary and grammar progression, CEFR and YLE alignment, World culture lessons

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Interactive science 2nd free?

Interactive science 2nd is free to download, with no in-app purchases.

### Is Let's Smile 4 free?

Let's Smile 4 is free to download, with no in-app purchases.

### Which has better reviews, Interactive science 2nd or Let's Smile 4?

Interactive science 2nd is rated higher. Interactive science 2nd averages 5.0 out of 5 from 1 ratings, while Let's Smile 4 averages 2.0 from 1 ratings.

### Do Interactive science 2nd or Let's Smile 4 have ads?

Neither Interactive science 2nd nor Let's Smile 4 shows ads.

### Which is updated more often, Interactive science 2nd or Let's Smile 4?

Interactive science 2nd ships an update every 30 months, and Let's Smile 4 every 19 months. Most recently, Interactive science 2nd was updated on September 28, 2026 and Let's Smile 4 on October 15, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*