Problem
㉠ sits at left 8, top 6, so its mirror cell is left 6, top 8, giving 48.
Folding lays ㉠ (left 8, top 6) onto the cell at left 6, top 8, and since swapping the order of multiplication never changes the product, those two cells always match.
Draw A Diagram3.OA.B.5Finding PatternsThe cell that lands on ㉠ when the table is folded holds the very same number as ㉠.
The fold lays ㉠, at left 8 and top 6, exactly onto the cell at left 6 and top 8, so those two cells are the pair that meets.
The fold line is the diagonal where the left number equals the top number, and folding lays one half of the table exactly onto the other half, so the cell that is 8 down and 6 across matches the cell that is 6 down and 8 across.
The meeting cell at left 6 and top 8 holds 6 times 8, ㉠ holds 8 times 6, and those two products are equal.
Swapping the two numbers being multiplied does not change the product, so 6 times 8 and 8 times 6 are the same number.
㉡ sits at left 6, top 7, so its mirror cell is left 7, top 6, giving 42.
The same rule applies to ㉡ — it meets the cell with its left and top numbers swapped, and 7 × 6 equals 6 × 7, so the two cells match.
Look For A Pattern3.OA.B.5Finding PatternsAdding the two meeting numbers, 48 and 42, gives 90.
The cell meeting ㉠ is 48 and the cell meeting ㉡ is 42, so the sum the problem asks for is just these two numbers added together.
3.OA.D.9Draw A DiagramFinding PatternsFolding just swaps the left and top numbers, and since multiplication doesn't care about order, the two cells that meet always hold the same number.