Elephants, Tigers, and Leopards
Class 4 · Mathematics
4 ideas in Class 4 Mathematics, explained in plain words, with games and quizzes to practise.
Adding 4-digit Numbers with Regrouping
Part of: Adding 4-digit numbers
To add big numbers we line up ones, tens, hundreds and thousands and add place by place, starting from the ones. When a place gives 10 or more, we regroup: 10 ones make 1 ten, 10 tens make 1 hundred, 10 hundreds make 1 thousand. For example, 18 ones is 1 ten and 8 ones.
Why it matters. Shopping bills, distances and school counts all use numbers in the thousands. Without regrouping, children drop the carried digit and get answers that are off by 10, 100 or 1000.
Try it in two minutes
- Make small paper tokens marked 1, 10, 100 and 1000, or use coins and notes of play money.
- Show 1275 with tokens and 1648 with tokens. Ask: how many ones are there altogether?
- Swap every 10 ones for 1 ten token. Ask: what do we do with the tens now?
- Keep regrouping up to the thousands and read the final number together.
Try at home. Ask your child to add the prices of three items from a shopping list, such as 1250, 2340 and 1115, and explain each regrouping.
Subtracting 4-digit Numbers with Regrouping
Part of: Subtracting 4-digit numbers
Subtraction also goes place by place from the ones. When the top digit is smaller than the bottom digit, we break 1 ten into 10 ones (or 1 hundred into 10 tens, or 1 thousand into 10 hundreds) and borrow. For example, in 62 minus 37 we turn 6 tens and 2 ones into 5 tens and 12 ones.
Why it matters. Finding how many are left, how much change to get, or how far is left to travel all need subtraction. Children who skip borrowing often subtract the smaller digit from the bigger one, which gives wrong answers.
Try it in two minutes
- Lay out 5 ten-tokens and 2 one-tokens for 52. Ask: can we take away 7 ones?
- Break one ten token into 10 one tokens. Ask: how many tens and ones do we have now?
- Take away 7 ones, then take away the tens, and read the answer.
- Check by adding the answer to the number you took away.
Try at home. Give your child 5000 rupees in play money and ask how much is left after spending 2764. Let them check the answer by adding.
More and Less Word Problems
Part of: More or less stories
In a story such as 'Tara has 400 more beads than Uma', the word more tells us the bigger number is found by adding. If we know the bigger number and want the smaller one, we subtract. Drawing two bars, a short one and a long one, makes the gap between them easy to see.
Why it matters. Comparing amounts is how we read data about animals, crops and crowds. Children who guess the operation from one word often add when they should subtract.
Try it in two minutes
- Pick two piles of coins, one with 12 and one with 5. Ask: which pile has more, and by how many?
- Draw one long bar and one short bar. Mark the extra part with a question mark.
- Make up a story: 'My pile is 7 more than yours.' Ask: do we add or subtract to find mine?
- Now make the same story with bigger numbers, such as hundreds.
Try at home. Ask your child to find two numbers in a newspaper or school book, say how much one is more than the other, and write the sum.
Smart Ways to Add and Subtract
Part of: Easy ways to add and subtract
Some sums are easier if we change a number to a round one and then fix the difference. To add 198, add 200 and take away 2. To subtract 99, take away 100 and add 1. We can also use a fact we already know: if 40 + 30 is 70, then 40 + 31 is 71.
Why it matters. Smart thinking makes mental maths faster and builds number sense. It also helps children check whether an answer is sensible before writing it.
Try it in two minutes
- Ask your child to find 50 + 49 without paper. Notice if they think 'one less than 50 + 50'.
- Ask for 80 minus 19. Show that taking 20 away and giving 1 back works.
- Say: 25 + 17 is 42, so what is 25 + 18? Let your child explain why it is one more.
- Repeat with bigger numbers such as 1000 or 2000.
Try at home. Give three sums that are close to round numbers, such as 399 + 250, and let your child find an easy way to solve each.
What your child will practise
- Adding 4-digit Numbers with Regrouping: Space Quick Fire (Quick Fire)
- More and Less Word Problems: Jungle Quick Fire (Quick Fire)
- More and Less Word Problems: Number Sort (Sort It Out)
- Smart Ways to Add and Subtract: Lab Explorer Quest (Collect the Answer)
- Subtracting 4-digit Numbers with Regrouping: Space Puzzle (Clue Puzzle)
- Quiz: Adding 4-digit Numbers with Regrouping (8 questions)
- Quiz: More and Less Word Problems (8 questions)
- Quiz: Smart Ways to Add and Subtract (8 questions)
- Quiz: Subtracting 4-digit Numbers with Regrouping (8 questions)