Number Play
Class 6 · Mathematics
4 ideas in Class 6 Mathematics, explained in plain words, with games and quizzes to practise.
Supercells: Bigger Than the Neighbours
Part of: Comparing neighbours
In a row of numbers, a cell is special if its number is larger than every cell touching it. Take the row 12, 30, 8. The 30 is larger than both neighbours, so it is special. The 12 is smaller than 30, so it is not. A cell at the end has only one neighbour to beat.
Why it matters. This game trains children to compare numbers carefully and to give reasons such as why the biggest number always wins. Without it, comparing is often done by guessing.
Try it in two minutes
- Write seven different numbers in a row on paper, for example 14, 52, 9, 33, 27, 61, 40.
- Ask your child to circle every number that is larger than the ones next to it.
- Ask: can the smallest number ever be circled? Why not?
- Now ask your child to write a new row with as many circled numbers as possible.
Try at home. Ask your child to write a row of eight different numbers that has exactly three circled numbers.
Digit Sums and Counting by Digits
Part of: Playing with digits
The digit sum of a number is what you get when you add its digits. For 482 it is 4 plus 8 plus 2, which is 14. Different numbers can share a digit sum: 59 and 68 both give 14. Children also learn to count how many numbers have two digits (from 10 to 99, so 90 of them).
Why it matters. Digit sums make children look at the digits instead of the whole number, which strengthens place value. Counting numbers by their digits builds careful, organised counting.
Try it in two minutes
- Pick a number from a calendar or a bus ticket and ask your child to add its digits.
- Ask your child to find another number with the same digit sum.
- Ask: what is the smallest 2-digit number with digit sum 9?
- Ask: how many numbers are there from 10 to 99? Let your child explain how they counted.
Try at home. Ask your child to write five numbers with digit sum 10 and say which one is the largest.
Palindromes and Reverse-and-Add
Part of: Palindromes
A palindrome is a number that reads the same from left to right and right to left, like 2552 or 626. In the reverse-and-add game you add a number to its reverse and repeat until you land on a palindrome. For example 29 plus 92 is 121, and 121 is a palindrome, so you stop.
Why it matters. Palindromes reward careful attention to the place of each digit and give lots of addition practice in a fun way.
Try it in two minutes
- Write 3-digit numbers like 454 and 463 and ask which one reads the same backwards.
- Pick a 2-digit number, for example 57. Ask your child to write its reverse and add.
- If the sum is not a palindrome, reverse it and add again.
- Ask how many steps it took.
Try at home. Ask your child to try reverse-and-add with their age or house number and count the steps.
Kaprekar's Routine and Collatz Sequences
Part of: Number rules and puzzles
In Kaprekar's routine you take a 4-digit number with at least two different digits, make the biggest and smallest numbers from its digits, and subtract. Repeating this leads to 6174. In the Collatz rule you halve an even number and, for an odd number, multiply by 3 and add 1. Start at 6 and you get 6, 3, 10, 5, 16, 8, 4, 2, 1.
Why it matters. Following a rule step by step without slips is the heart of careful calculation. These puzzles make subtraction, place value and even-odd thinking more fun.
Try it in two minutes
- Choose a 4-digit number such as 7352 and ask your child to write the largest number from its digits.
- Then write the smallest number and subtract.
- Repeat with the answer and watch where it ends.
- Try the halve-or-triple rule with 12 and check whether you reach 1.
Try at home. Ask your child to try the Collatz rule on 9 and count how many steps it takes to reach 1.
What your child will practise
- Digit Sums and Counting by Digits: Ocean Quest (Flip and Match)
- Palindromes and Reverse-and-Add: Mirror Sort (Sort It Out)
- Palindromes and Reverse-and-Add: Space Puzzle (Clue Puzzle)
- Palindromes and Reverse-and-Add: Space Quick Fire (Quick Fire)
- Supercells: Bigger Than the Neighbours: Number Quest (Collect the Answer)
- Quiz: Digit Sums and Counting by Digits (8 questions)
- Quiz: Kaprekar's Routine and Collatz Sequences (8 questions)
- Quiz: Palindromes and Reverse-and-Add (8 questions)
- Quiz: Supercells: Bigger Than the Neighbours (8 questions)