A 6×6 digit grid reads 5 7 5 5 8 2 / 1 7 9 2 6 7 / 2 5 8 2 5 3 / 5 8 7 9 9 6 / 4 2 4 8 9 0 / 3 4 2 1 5 4 by rows. Group digits that run consecutively along one row or one column and insert only a + and an =, making a two-digit number plus a one- or two-digit number. Row 2's 1, 7, 9, 2, 6 is the worked example, 17 + 9 = 26. Find four more true equations of this kind.
Your answer
Watch outCherry-picking digits is tempting, but the window must stay consecutive — and diagonals do not count.
How to solve
StrategyMake a Systematic List — The search space is small and finite: each line has only a handful of consecutive windows and only a few ways to place the + and =. Listing the windows row by row and column by column (tool 2) guarantees we miss none, and for each window we simply test whether a placement makes the sum work (tool 6).
1STEP 1
Re-read the example to fix the rule
The example fixes the shape: the + follows a two-digit chunk and the rest sits after the =.
17 + 9 = 26
Pinning down the exact pattern from the example turns a vague puzzle into a small checklist of 'cut here, add, equals'.
2.NBT.B.5Make A Systematic List
2STEP 2
Scan the rows for a working cut
Row 4, 5 8 7 9 9 6, yields 87 + 9 = 96.
87 + 9 = 96
Adding a single digit to a 2-digit number and crossing one ten (87 to 96) is a quick within-100 check, so testing each window is fast.
42 + 48 = 90 because 42 + 48 = 40 + 50 = 90 (the ones 2 and 8 make a ten), an easy mental add within 100.
2.NBT.B.5Guess And Check
42 plus 48 lands on 90 because the two ones digits make a full ten that moves up into the tens place.
Why?
Ten ones do not stay in the ones place — they become one ten and join the tens column, leaving nothing behind.
🧱Place-value groupingTen ones make one ten and ten tens make one hundred — each place bundles ten of the last.
Why?
You may also read it as moving 2 from 42 over to 48, turning the pair into 40 and 50 without changing what they add to.
🧱What one part gains the other losesMove some amount from one addend to the other and the total does not budge, so you may make one number round for free.
Each equation is checked by direct addition: 87+9=96, 42+48=90, 77+5=82, 52+29=81 — all true. Each uses only consecutive digits in one line: row 4 (8,7,9,9,6), row 5 (4,2,4,8,9,0), column 2 (7,7,5,8,2), column 4 (5,2,2,9,8,1). None begins a multi-digit number with 0, and all match the (2-digit)+(1 or 2-digit) form, so the four are valid and distinct from the example.
Takeaway
List every consecutive chunk and just test each one — checking sums within 100 is Grade 2 mental math you already know!