by Maurici Carbó (nummòlt) app developer
Double interactive place value chart, with up to 40 decimal columns.
- Show and experience the addition and addition with carry.
- Show and experience the subtraction and subtraction with borrowing.
- Zero as "nothing" in a place value place, or as negative-positive pairs of Tokeens or Places with sign.
Two configurations: Standard and J. LeMieux version:
Change the version, upper back arrow, or at the menu option.
S T A N D A R D . . . . C O N F I G U R A T I O N :
(Positive and negative Tokens, and Places without sign)
Each chart with a variable number of places.
In the places, a variable number of tokens with positive or negative value
A token can be positive or negative.
A positive token is born with the tap of a finger on the screen
A pair of positive-negative tokens is born with a tap of two fingers on the screen
A token disappears if it crosses the top or bottom border.
The behavior of tokens:
Positive and negative tokens have the same behavior:
A token can cross at will the intermediate horizontal border
When a token crosses the border on the right, it becomes 10 tokens.
A token need 9 companions from the old place to cross the border to the left.
Positive and negative tokens may be in the same place.
But if two tokens of different signs meet, they cancel each other.
A place can contain tokens of the same or different sign.
The upper and the lower borders can be the external border or the intermediate border.
Tokens can cross freely the intermediate border.
If a token cross the external border, disappears.
To get the permission to cross left borders, a token needs 9 companions of the same sign.
A token recovers 9 companions if cross the right borders.
There are two charts: The upper chart and the lower chart.
There is a button in each chart to change the sign of all its tokens.
L E . M I E U X . . . . . C O N F I G U R A T I O N :
(colored Tokens without sign, and Places with sign)
All the Places of each chart can be positive or negative.
A pair of tokens is born with a tap of two fingers on the screen over two places of different sign.
The behavior of tokens:
A token can cross at will the intermediate horizontal border if the places have the same sign.
When a Token tries to cross the border to a Place of a different sign, calls another Token of the other Place, and they cancel each other in the border.
A place can contain not signed colored tokens.
Tokens can cross freely the intermediate border if the sign of the two places are the same.
There is a button in each chart to change the sign of all its Places.
In the 'settings' option, there is an option to erase all tokens of each chart, or to erase all tokens and refresh all to start again from scratch.
Touch decimals Place value ±
The behavior of places and tokens of this app describes the behavior of the numbers in the decimal system.
Math 1, 2, 3, 4 Number sense: Place value.
Math 5, 6, 7 Base Ten:
** COMMON CORE State standards initiative:
Understand place value:
Use place value understanding and properties of operations to add and subtract: CCSS.MATH.CONTENT.1.NBT.C.4; CCSS.MATH.CONTENT.1.NBT.C.5; CCSS.MATH.CONTENT.1.NBT.C.6
** Grade 2:
Place value understanding and properties of operations to add and subtract:
CCSS.MATH.CONTENT.2.NBT.B.5; CCSS.MATH.CONTENT.2.NBT.B.6; CCSS.MATH.CONTENT.2.NBT.B.7; CCSS.MATH.CONTENT.2.NBT.B.9
** Grade 3:
Use place value understanding and properties of operations to perform multi-digit arithmetic.
** Grade 4:
Developed by: http://www.nummolt.com
Nummolt Blog: Mathematical engine mill: