Sensim Math · Depth 한국어

2-2 · Tables and Graphs

Total equals the sum of the rows

2.MD.D.102.OA.A.1 · take · grade 2

Archetype: Read and Scale a Data Graph · step in a 21-type progression

▶ Practice — 12 problems

Mason and his friends counted how many strawberries each of them picked at a weekend farm and recorded the results in a table. If Mia picked 44 more strawberries than Emma, how many strawberries did Hana pick?

Number of strawberries picked at the weekend farm

Name Mason Mia Emma Hana Total
Strawberries 99 77 3535
Show solution

Understand

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.

Givens
  • Mason = 9, Emma = 7 strawberries.
  • Total for all four = 35.
  • Mia picked 4 more strawberries than Emma.
Unknowns
  • How many strawberries Mia picked.
  • How many strawberries Hana picked.
Constraints
  • The total equals the sum of all four people's counts.

Plan

#7 Identify Subproblems · also uses: #11 Work Backwards

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.

Execute

#7 Identify Subproblems 2.OA.A.1
Mia picked 4 more than Emma's 7: 7 + 4 = 11 strawberries.
7+4=117 + 4 = 11
'4 more' means add 4 to Emma's count.
#7 Identify Subproblems 2.MD.D.10
The four counts add to 35. Subtract Mason and Emma: 35 - 9 - 7 = 19, which is Mia plus Hana.
35−9−7=1935 - 9 - 7 = 19
The total minus the two known rows leaves the other two rows combined.
#11 Work Backwards 2.OA.A.1
Mia plus Hana is 19 and Mia is 11, so Hana = 19 - 11 = 8 strawberries.
19−11=819 - 11 = 8
Working backwards from the pair total and the known Mia gives Hana.
Answer: 8 strawberries

Review

Check the full table: 9 + 11 + 7 + 8 = 35, matching the total, and Mia (11) is 4 more than Emma (7). Both conditions hold.

Subtract all three known/derived counts from the total at once: 35 - 9 - 11 - 7 = 8 for Hana — same answer.

Standards · min grade 2

  • 2.MD.D.10 Draw and interpret picture graphs and bar graphs — Using the table's total as the sum of its rows to set up the missing values.
  • 2.OA.A.1 Solve one- and two-step word problems using addition and subtraction within 100 — Finding Mia from '4 more than Emma' and subtracting to reach Hana.
💡 This only needs the Grade 2 idea that a table's total is the sum of its rows — then add and subtract!