Grade 5 · Math · Unit 2 of 13
Add & Subtract
Big sums, differences and estimates
What your child practises
Adding and subtracting numbers up to 1 000 000 with regrouping (including across zeros), estimating by rounding, and mental math such as compensation (adding 4999 as 5000 − 1).
Nunavut Curriculum approved guide: Alberta Mathematics K–9 (2007), Number · estimation strategies, and adding and subtracting decimals
How we explain it
Children can open this short lesson before they practise.
- Line up the digits by place value.
- Add or subtract from the ones place and move left, regrouping when you need to.
- Estimate first by rounding, then check your answer is close.
Example: 48 000 + 27 500 = ? Estimate: 50 000 + 30 000 = 80 000. Add 48 000 + 27 500 = 75 500. 75 500 is close to the estimate. Answer: 75 500
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
What do you add to 76 500 to make 100 000?
76 500 + = 100 000
answer box
23500
Hint: Count up in friendly jumps: first to the next round number, then on to 100 000. Add up all your jumps.
Question 2
Subtract: 526 098 − 507 362
Line up the places HTh TTh Th H T O 5 2 6 0 9 8 − 5 0 7 3 6 2 answer box
18736
Hint: Start with the ones. When the top digit is too small, regroup 1 from the next place (across zeros if needed). Check by adding your answer to 507 362.
Question 3
A city has 587 866 adults and 311 248 children. How many people live in the city?
answer box
899114
Hint: The total of two amounts means add. Line up the places and add from the ones, regrouping as you go.
Question 4
A school wants to collect 75 000 cans of food. Grade 4 collected 15 137 and Grade 5 collected 14 984. How many more cans do they need?
- 30 121
- 59 863
- 45 879
- 44 879
44 879
Hint: This takes two steps. First add the two amounts collected. Then subtract that total from the goal.
Question 5
A stadium has 802 310 seats. So far, 218 184 tickets have been sold. How many seats are still available?
answer box
584126
Hint: Finding a difference or how many more means subtract the smaller amount from the greater one. You can also count up from the smaller number.
Question 6
Round each number to the nearest ten thousand, then add. What is the estimate for 285 920 + 207 968?
- 500 000
- 510 000
- 480 000
- 490 000
500 000
Hint: Round each number first: look at the digit to the right of the ten thousands place. Then add the rounded numbers.