Express $100$100 in the expanded form using index notation.

Express $1000$1000 in the expanded form using index notation.

Write the number expressed by: $2\times10^4+2\times10^3+7\times10^2+7\times10^1+6\times1$2×104+2×103+7×102+7×101+6×1.

Note: Do not use comma separators

Write the number expressed by: $3\times10^4+2\times10^3+9\times10^1+5\times1$3×104+2×103+9×101+5×1.

Know counting sequences for whole numbers.