5.NBT.A.2 math practice. Learn by doing.

Multiplying by $10^{2}$ appends $2$ zeros to the whole number: $4 \times 10^{2} = 400$.

$10^{1}$ means $1$ followed by $1$ zero, so $10^{1} = 10$.

Multiplying by $10^{2}$ appends $2$ zeros to the whole number: $8 \times 10^{2} = 800$.

$10^{2}$ means $1$ followed by $2$ zeros, so $10^{2} = 100$.

Multiplying by $10^{3}$ appends $3$ zeros to the whole number: $9 \times 10^{3} = 9000$.

$10^{3}$ means $1$ followed by $3$ zeros, so $10^{3} = 1000$.

Multiplying by $10^{3}$ appends $3$ zeros to the whole number: $8 \times 10^{3} = 8000$.

$10^{4}$ means $1$ followed by $4$ zeros, so $10^{4} = 10000$.