# Exploring The Core K vs Number Rack, by MLC

The clearest difference is rating: Exploring The Core K at 4.4 against Number Rack, by MLC's 3.2. Exploring The Core K also leads on update cadence (every 5 weeks vs every 25 months) and device support (3 vs 1). Number Rack, by MLC's advantage is review sentiment (100% vs 60%) and in-app purchases (none vs 1). On price, ratings volume and ads there is nothing between them.

Both are free to download. Exploring The Core K sells 1 one-off in-app purchase. Number Rack, by MLC asks for nothing beyond the download.

Exploring The Core K holds the better App Store score, 4.4 against 3.2. Both are backed by a comparable volume of ratings — 7 and 9 respectively. Written reviews complicate that: 60% of Exploring The Core K's written reviews are positive against 100% of Number Rack, by MLC's, so the app with the better star average is not the one people write more warmly about.

Exploring The Core K ships an update every 5 weeks, Number Rack, by MLC every 25 months. The most recent releases landed on September 26, 2026 and October 14, 2026 respectively.

## The numbers

| Metric | Exploring The Core K | Number Rack, by MLC |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (7 ratings)](https://appshunter.io/ios/app/exploring-the-core-k-8-math/id1093007771/reviews)** | [3.2 (9 ratings)](https://appshunter.io/ios/app/number-rack-by-mlc/id1469094747/reviews) |
| Number of ratings | 7 | **9** |
| Positive reviews | 60.0% of reviews | **100.0% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 5 weeks** | Every 25 months |
| Monetization | Free with in-app purchases | **Free** |
| Size | 35 MB | 4 MB |
| Requires iOS | **8.0** | 14.7 |
| Devices | **iPhone, iPad, iPod** | iPad |
| Age rating | 4+ | 4+ |
| Developer | [Exploring The Core LLC](https://appshunter.io/developer/1093007710) | [The Math Learning Center](https://appshunter.io/developer/1542700905) |

## What reviewers say

### Exploring The Core K

[App page](https://appshunter.io/ios/app/exploring-the-core-k-8-math/id1093007771)

This app visualizes Common Core State Standards for K-8 math, showing skill progression across grade levels. It serves as a reference for parents and educators to understand expected math skill sets.

**Highlights:** Visualizes K-8 math standards, Shows skill development across grades, Searchable standards, Glossary of education terms, Reference tool for parents and teachers

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock All Grades and Skills | $2.99 | one-time |


### Number Rack, by MLC

[App page](https://appshunter.io/ios/app/number-rack-by-mlc/id1469094747)

This virtual manipulative tool helps children develop number sense through interactive bead groupings. It supports exploration of addition and subtraction strategies with customizable rows and colors. Ideal for elementary classrooms, it includes annotation and sharing features.

**Highlights:** 1-10 rows of 10 beads, Resizable bead covers for subtraction, Color-coded bead rows, Annotation and drawing tools, Math text and writing tools, Shareable work via image or code

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Exploring The Core K free?

Exploring The Core K is free to download, with in-app purchases available.

### Is Number Rack, by MLC free?

Number Rack, by MLC is free to download, with no in-app purchases.

### Which has better reviews, Exploring The Core K or Number Rack, by MLC?

Exploring The Core K is rated higher. Exploring The Core K averages 4.4 out of 5 from 7 ratings, while Number Rack, by MLC averages 3.2 from 9 ratings.

### Do Exploring The Core K or Number Rack, by MLC have ads?

Neither Exploring The Core K nor Number Rack, by MLC shows ads.

### Which is updated more often, Exploring The Core K or Number Rack, by MLC?

Exploring The Core K ships an update every 5 weeks, and Number Rack, by MLC every 25 months. Most recently, Exploring The Core K was updated on September 26, 2026 and Number Rack, by MLC on October 14, 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.*