NCERT Solutions for Class 5th Maths Chapter 5 The operation-sign puzzle — Try This
Book page 69 Updated on2026-09-19
Q1.
Put appropriate operation sign (+, –, ×, ÷) such that each row and column and each 4 × 4 box should not repeat the sign. (The grid is given with ÷ in row 1 column 1, + in row 1 column 4, × in row 2 column 2, + in row 3 column 3, and – in row 4 column 4.)
The 4 × 4 grid printed on page 69, with five signs already filled in.
Answer
Here is the completed grid. Every row has all four signs, and so does every column.
Column 1
Column 2
Column 3
Column 4
Row 1
÷
–
×
+
Row 2
+
×
–
÷
Row 3
–
÷
+
×
Row 4
×
+
÷
–
Black signs were printed in the book. Red signs are the ones you work out.
How to find them, one clue at a time.
Row 1 already has ÷ and +. So the two empty places must hold – and ×, in some order.
Look down column 2. Row 2 already has ×. So row 1 column 2 cannot be ×; it must be –. That leaves × for row 1 column 3.
Look down column 4. It has + at the top and – at the bottom, so the two middle places take × and ÷. Row 2 already has ×, so row 2 column 4 must be ÷, and row 3 column 4 must be ×.
Row 2 now has ×, ÷. The two left places take + and –. Column 3 already has × and + in it, so row 2 column 3 must be –. That leaves + for row 2 column 1.
Column 1 has ÷ and +. Row 3 column 1 must be – or ÷, and ÷ is already used in that column, so it is –. Then row 3 column 2 is ÷, and row 4 column 1 is ×.
Row 4 now has × and –. Column 2 already has –, ×, ÷, so row 4 column 2 is +, and row 4 column 3 is ÷.
The one idea behind the whole puzzle: Every time, ask "which signs are already used in this row and in this column?" Cross those out. If only one sign is left, you have found the answer. This is how every Sudoku-style puzzle is solved — never by guessing.
Check it yourself: Read each of the four rows aloud, and then each of the four columns. Every one should contain +, –, × and ÷ exactly once. Row 3, for example, is –, ÷, +, × ✓
About the wording: The book says "each 4 × 4 box", but the whole grid is the only 4 × 4 box there is. The real conditions are the ones we used — no sign twice in any row, and none twice in any column. More than one filling is possible; the one above is a correct answer.