Provide the students with pencil and paper. Read aloud this story: Long, long ago the ruler of a prosperous land decided to build a new castle. He hired an overseer to keep count of the number of stone blocks brought in. Remember, there was no number system in those days. The overseer took a large stone tablet and a sharp-edged stone. He sat at the gate. For every stone block he made one scratch. (Ask the students to draw a line). After every four scratches he drew a horizontal line. (Show the students how to do that). Soon the tablet was filled with scratches. He got a new tablet. (Make the students fill a sheet of paper). The overseer got tired of filling up tablets with scratches. He stared at his tired hands, thinking of an easier way to keep count. He got it. "I know", he said, "I have 10 fingers and can count up to 10. (Make the students count on their fingers).
Base ten is a decimal system that depends on place value. Revise the concept of place value with this riddle:
Hand each student a graph paper. For a beginning class, mark the columns with the place value headings: Ones, Tens, Hundreds, Thousands, going from right to left. Say that you will read out a riddle. They have to solve the riddle and write the number in the correct column..
1. I am the odd number between four and six. What am I? (They guess five and write five in the ones column).
2. I am less than nine but more than five. I am an odd number. What am I? (Seven).
3. I am a double-digit number. I am less than 14 but more than 11. I am an even number. What am I? (12). Check that the one is written in the ten's column, and the two in the one's column.
You can add riddles of greater complexity, depending on the skill level of the students.
I am greater than 12, less than 21. I am an odd-number, but the sum of my digits is six. What number am I? (15)
Read me backwards, read me forwards
I still look the same.
I lie between 10 and 20
And odd is my name. (11)
Take the number of hours in a day. Add the number of minutes in an hour. Add the number of seconds in a minute. I become the answer to 12 times 12. What number am I? (144).
Ask the students to write down a pair of numbers:. For example take 345 and 543. Then ask them to write each digit separately. Point out that they used the same three digits 3,4 and 5, but the place they put the digits created two different numbers. Create more digit pairs to reinforce this concept. Then play this blackboard riddle game:
Draw four boxes on the blackboard. Label the boxes ones, tens, hundreds and thousands. Read a riddle. Ask for volunteers to write the answer in the boxes.
1.The number of hours in a day.
2.The number of days in a year.
3.The number of fingers plus the number of toes.
4.Write in the thousands box the total of the number of eyes and the number of ears on a face.
Add more riddles as you go along.