Write 4008 in expanded form using powers of 10. Explain for a grade 5 learner.

The number 4008 has a 4 in the thousands place, 0 in the hundreds place, 0 in the tens place, and 8 in the units place.

"Four thousand and eight" correctly represents the value of 4008.

The answer by the learner is ✅ Correct. The number 4008 is read as "four thousand and eight" because the zeros in the hundreds and tens places indicate no value in those positions, so they are not explicitly named when reading the number.

In 4008, the digit 4 is in the thousands place ($10^3$), the first 0 is in the hundreds place ($10^2$), the second 0 is in the tens place ($10^1$), and the digit 8 is in the units place ($10^0$).

Since $0 \times 10^2 = 0$ and $0 \times 10^1 = 0$, these terms can be omitted when explaining to a grade 5 learner.

Expanded form: $\boxed{(4 \times 10^3) + (8 \times 10^0)}$
Explanation for a grade 5 learner: We break the number into its parts. The 4 is in the thousands place, so it's $4 \times 1000$ (which is $4 \times 10^3$). The 8 is in the ones place, so it's $8 \times 1$ (which is $8 \times 10^0$). The zeros mean there are no hundreds or tens.

Removing both zeros from 4008 leaves the digits 4 and 8.

The new number formed is 48.

The original number was 4008. The new number is 48. Removing the zeros makes the number much smaller because the 4 moves from the thousands place to the tens place, and the 8 moves from the units place to the units place, but its value is now relative to the 4 in the tens place. The value changed from four thousand and eight to forty-eight.

The new number is $\boxed{48}$. The effect is that the value of the number becomes significantly smaller. The digit 4, which was in the thousands place, moves to the tens place, reducing its value from 4000 to 40.