PlusyQuestions worked in columns
Plusy sets out bigger questions in columns, the way they are written on paper, with one answer box per digit. Your child fills the boxes from the ones leftward, and the question checks itself when every box is right.
Which questions open in columns?
Plusy opens a question in columns when it is too big to answer from memory. Small facts such as 7 + 8, 25 − 4 or 6 × 7 stay on one line.
- Addition and subtraction: when both numbers have two or more digits, or either has three or more.
- Multiplication: when either number is above 12.
- Division: when the divisor or the answer is above 12.
What do the letters above the columns mean?
The letters above the columns are place-value labels. O is ones, T is tens, H is hundreds, Th is thousands and TTh is ten thousands. Under them are the numbers, a line, and one answer box for each digit of the answer.
The cursor starts on the ones and moves left by itself to the next empty box, in the order the sum is solved. Your child can also tap any box to work there.
What are the small boxes above the numbers?
The small boxes above the columns are carry boxes in addition and multiplication, and borrow boxes in subtraction. They are your child's own working, like the little digits written above a sum on paper. Leaving one empty is never counted as a mistake.
TTh Th H T O
1 1 1
7 2 8 5
+ 4 9 6 8
-------------------
1 2 2 5 3In subtraction, a borrow box can hold two digits, such as 13, and a value typed there strikes out the digit under it. The hardest case is borrowing across a zero:
H T O
4 9 13
5 0 3
- 1 2 7
-------------
3 7 6How are long multiplication and long division set out?
Long multiplication in Plusy has one working row for each digit of the multiplier, and then the rows are added. Long division has the quotient on top and working rows below, and the rows appear one at a time as each one is filled.
In long division the answer is typed from the left, the way it is worked out. The layout follows the language: English uses the bracket layout, and Hebrew uses the layout taught in Israel. On the roads every division comes out even. In your own lists a division can leave a remainder, written after an R.
What happens when my child types a wrong digit?
Plusy marks a wrong digit gently while your child is still solving. The box gets a soft orange border and one line says Check this one again. There is no red, no cross and no sound, and nothing is counted as a mistake until the answer is checked.
After the check, right digits get a tick, and a wrong digit is shown small and struck through beside the right one. Carry and borrow boxes are marked the same way, so your child sees exactly where the working went off.
Can my child use the columns on a multiple choice question?
Yes. When a big question is multiple choice, the answer boxes are scratch paper. On a phone or tablet the line Tap a box to work it out. shows under the grid until your child taps a box. The number pad then opens in place of the choices, and Answers brings them back. When the row your child worked out matches one of the choices, Check picks that choice.
Why did the question check itself?
A column question checks itself once every answer box holds the right digit, after a short pause. A full row with a wrong digit in it waits for your child to press Check. While some boxes are still empty, the button reads Keep solving and moves the cursor to the first empty box.
A child who is stuck can ask for one step at a time: see Stuck? Hint, Show me and Next step.
Questions
My child's school sets out sums differently. Will Plusy confuse them?
Addition, subtraction and multiplication use the common column layout with carrying and borrowing above the numbers. Long division uses the bracket layout in English and the Israeli layout in Hebrew. If the school's layout differs, sit in on the first few questions.
Does my child have to fill in the carry boxes?
No. Carry and borrow boxes are optional working. A child who carries in their head can leave them empty and the answer is still right. When they are used, Plusy checks them too, which helps it explain a slip.
Are there remainders in long division?
In your own lists, yes: type or scan 815 ÷ 2 and the answer is 407 R1. On the roads every division comes out even.
How big do the numbers get?
The largest answer anywhere in Plusy is 99,999, five digits. The roads reach four-digit addition and subtraction, three digits times two digits, and division by two-digit numbers.