Answer:
43
Step-by-step explanation:
Let's call this number x. The word sum means addition, so we can write x + 21 = 64. When we subtract 21 from both sides, we get x = 43. Hope this helps!
Answer:
the number equals 43
Step-by-step explanation:
We can write the sentence in mathematical terms to get a formula, using "x" for the unknown:
x + 21 = 64
Then we solve for x by subtracting 21 from oth sides of the equation:
x = 64 - 21
x = 43
