How to play Maths Duel

A race is the way to play against the bot or a friend online.

1. The slip counts in, three, two, one.
2. A sum goes up. Type the answer, and the moment it is right the next sum takes its place.
3. Keep going until your time runs out. Your tally lane on the slip gains a stroke for every right answer, and so does the other player’s.
4. When both of you are out of time, the one with more right wins.

Each of you works down the list at your own pace, so neither waits for the other. Online, your own time starts when your phone has counted in, so a slow connection costs you nothing.

There is no enter key. Type the digits and the answer counts the moment they are right, with a green line drawn under it.

Type as many digits as the answer has and get them wrong, and it is a miss. The box shakes, the digits are struck through in red, and the keypad holds for half a second before it clears. At the buzzer the hold is a whole second.

No marks are taken off for a miss. The time it costs is the penalty, and it makes guessing slower than working it out. The key with the arrow takes back a digit you typed by mistake.

Every answer is a whole number of one to three digits, and never below nought. Sharing always comes out exactly.

• Easy: adding and taking away under twenty, and times tables up to five.
• Medium: two digits and two digits, and times tables up to twelve with their sharing.
• Hard: three digits and two, change from a thousand-rupee note, two digits times one, the teens times the teens, and squares up to twenty-five.

On the game page you can choose to have only adding and taking away, or only times and sharing. Whatever you choose, both players get exactly the same sums.

In a race, whoever has more right answers when their time is up wins.

If you finish level, the one who reached that score sooner wins, each timed from their own start. Level on both is a draw, and so is a race where nobody got any right.

At the buzzer the first to the target wins. Online, a player who leaves and does not come back loses the race to the one who stayed.

The slip in the middle shows the sum, your answer box, both tally lanes and the clock. The rule along the top of the window shortens as the time runs, and it turns red for the last ten seconds.

The keypad is at the foot of the screen, laid out like a phone’s with 1, 2 and 3 across the top. On a computer the number keys type and Backspace takes a digit back.

On a sideways phone the keypad goes down the side of the screen, on the side of your writing hand.

Watch mode sets two bots racing each other, which is a quick way to see what a quick player’s minute looks like.

• Learn the times tables up to twelve by heart. Half the sums at medium are a table you either know or work out.
• For adding, take the tens first and the units after: 48 and 37 is 70, then 15, so 85.
• For change from a thousand, take each digit from nine and the last from ten: 1000 take away 365 is 635.
• Do not guess. A miss holds the keypad for longer than most sums take to work out.
• Keep your eyes on the slip and your thumb on the keypad. Looking down at the keys between answers is time.

Everything on the game page, before you press Play.

Race

The way to play where each player gets the same list and a time of their own, and the most right wins.

Buzzer

The way to play where one sum goes up for both, and the first right answer takes it.

Slip

The piece of paper on the table with the sum, the answer box, the tallies and the clock on it.

Tally

A count kept in strokes, four upright and the fifth across them, the way a scorer keeps one.

Miss

An answer with as many digits as the right one that is not it. It costs a moment and no points.

Carry

In adding, the ten that goes over into the next column when the units come to ten or more. In taking away, the ten borrowed back.

Change

What a shopkeeper gives back from a note. In hard sums, what is left of a thousand rupees.