Let's call your number n. Twice your number is 2n. The product of your number and twice your number (so n multiplied by 2n) is 128.
Set up an equation:
n × 2n = 128
2n² = 128
Divide both sides by 2:
n² = 64
Square root both sides to isolate n:
n = 8
The question asks for half your number, so just half 8:
8 ÷ 2 = 4.
Half your number is 4.
The Moon appears to change shape because we see different amounts of the lit part as the Moon orbits Earth. From Earth's perspective, we see varying amounts of the illuminated part of the Moon.
