Let Lewis's sweets be "n"
Given,
Rosie's sweets = 20
Chloe's sweets = 49
Lewis's sweets = n
Total sweets = 69
So,
20 + 49 + n = 69
→ 69 + n = 69
→ n = 69/69
→ n = 1
But this is not possible, as if Lewis sweets (n) is 1 , then 20+49+1 = 70, which is not equal to the total number of sweets.
Therefore, we can assume that the number of sweets Lewis got will be 0 sweets .
Then only it will satisfy the L.H.S and R.H.S, as they both will be equal.
By Benjemin ☺️