Start by teaching kids the number one (1). Say the number out loud and have them copy it. Have them write it on a whiteboard or large paper.
2. Next, ask them to spell the number two (2). Have them say and write the letter two twice on the whiteboard or paper.
3. Have them spell the next two numbers, three (3) and four (4), the same way.
4. After they have learned all of their number spelling, slowly start introducing more complex numbers. Have kids spell 1-10 and then move onto 20, 30, 40, 50 and 60. Then continue with 100, 500, 1000 etc.