Problem
Total equals the sum of the rows
A table lists strawberries picked: Mason 9, Emma 7, total 35, with Mia and Hana blank. Mia picked 4 more than Emma. I need how many Hana picked.
Measurement & dataOperations
Your answer
strawberries
Watch out The clue points at Mia, so it is easy to solve for Mia and stop — but the question asks for Hana.
How to solve
Strategy Identify Subproblems — Find Mia from the '4 more than Emma' clue, then use the fact that the total is the sum of the rows to work backwards to Hana. Two small subtraction/addition subproblems.
1STEP 1
Find Mia
Mia picked 4 more than Emma's 7: 7 + 4 = 11 strawberries.
7 + 4 = 11
'4 more' means add 4 to Emma's count.
2.OA.A.1Identify Subproblems2STEP 2
Find Mia and Hana together
The four counts add to 35. Subtract Mason and Emma: 35 - 9 - 7 = 19, which is Mia plus Hana.
35 - 9 - 7 = 19
The total minus the two known rows leaves the other two rows combined.
2.MD.D.10Identify SubproblemsTaking Mason's 9 and Emma's 7 away from the total 35 leaves exactly Mia and Hana's counts added together.
Why?
The total 35 is just the four people's counts added up, so it is made of exactly those four parts.
Why?
Every strawberry in the total belongs to one and only one of the four people, so the four counts fill the total with no gaps and nothing counted twice.
🧱Whole is the sum of its partsBreak a thing into pieces with no gaps or overlaps and the pieces add back to the whole.
Why?
Because the total is those four parts added, taking the two counts you already know back out leaves the two counts you don't.
Why?
Taking a number away cancels having added it, so subtracting Mason's 9 and Emma's 7 undoes adding them and only Mia's and Hana's counts remain.
🧱Inverse operationsSubtraction undoes addition and division undoes multiplication — they reverse each other.
3STEP 3
Find Hana
Mia plus Hana is 19 and Mia is 11, so Hana = 19 - 11 = 8 strawberries.
19 - 11 = 8
Working backwards from the pair total and the known Mia gives Hana.
2.OA.A.1Work BackwardsAnswer
8 strawberries
19 - 11 = 8
Check the full table: 9 + 11 + 7 + 8 = 35, matching the total, and Mia (11) is 4 more than Emma (7). Both conditions hold.
Takeaway
This only needs the Grade 2 idea that a table's total is the sum of its rows — then add and subtract!
- Find Mia
- Find Mia and Hana together
- Find Hana
Where next?
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