Math Tablet: Part-Whole Model

Two parts make a whole. Addition and subtraction are built on this relationship – and Math Tablet makes it visible. Children put counters on the two halves of a tray; the whole is at the top, the parts below. Every action on the material changes the numbers straight away.

The idea goes back to the "Rechentablett" by Gerster and Schultz. The first app appeared in 2012; this new edition is an open environment for exploring elementary math with the part-whole model.

LESS IS MORE
At first the tray looks like the original: counters to 20, numbers visible, nothing else. Adults switch on everything else in Settings – or an investigation brings it along.

WITH ALL YOUR FINGERS
• Tap to put down a counter, with several fingers several at once
• Drag counters to the other side – several at the same time
• Drag out to take away, shake to clear the tray

COVER AND WORK IT OUT
A shutter covers one side, and numbers can be covered too. To uncover, children first enter how many they think are hidden. Every tray becomes a missing number problem.

PLACE VALUE TO 1000
Up to 100 and 1000 the material grows out of the counters: ten ones move together and become a ten strip, ten tens a hundred frame. Tap a ten to open it again. "Arrange" lays out hundreds, tens and ones side by side as in a place value chart.

44 INVESTIGATIONS
For Grades 1 to 4: find all number bonds, work out hidden parts, change calculations and explain what stays the same, make ten or a hundred, quick looks. Many investigations end with a question that asks for reasoning. The overview highlights what suits the chosen number range.

NO POINTS, NO STARS
Feedback describes in mathematical language what has changed on the material ("5 + 3 = 8 has become 4 + 4 = 8."). It never gives away a solution or a discovery.

FOR SCHOOL
• Sentence frames read aloud: "The whole is 8. The parts are 5 and 3."
• Number sentences with boxes for covered numbers, fact families
• Lock the whole, roll, surprise
• Link and QR code for a prepared tray on every device in the class
• Settings behind an adult lock (press and hold for 3 seconds)
• English and German

PRIVACY
• No ads
• No tracking
• No in-app purchases
• No sign-in
• No internet connection needed
• All data stays on the device

Developed by Christian Urff, mathematics educator and developer of virtual manipulatives for elementary math.