Build on students' understanding of the power of ten within multiplication to understand its effect within division. Use this as a standalone lesson or as support to the lesson Dividing Decimals by Powers of 10.
Students will be able to discuss the powers of 10 and explain decimal placement patterns in the quotient.
Students will be able to discuss decimal placement patterns using sentence stems and vocabulary instruction.
Display the answer sheet for the Growing by Powers of Ten Chart worksheet and discuss what they see happening to the numbers as they are multiplied by 10 in the standard form column (e.g., the number gets larger by adding more zeros, but the rest of the digits stay the same). Focus on the standard form column so students can notice the pattern.
Remind students about the inverse relationship between division and multiplication with simple calculations (e.g., 5 x 5 = 25 and 25 ÷ 5 = 5). Ask students to discuss how the product is different from the factor, and how the quotient is different from the dividend (e.g, "The product is bigger than both of the factors, while the quotient is smaller than the dividend.").
Refer back to the answer sheet of the worksheet Growing by Powers of Ten Chart. Have students turn and talk to their partners regarding the following question: "What would happen to the quotient if I changed all the multiplication problems to division problems?"
Explain to students that the worksheet shows the power of ten for multiplication, but the power of ten also applies in division as well. The quotient will get smaller and smaller exponentially as the dividend is divided by ten (e.g., 234.5 ÷ 10 = 23.45 and 23.45 ÷ 10 = 2.345). Tell them they will begin to notice patterns for decimal point movement within division by the end of this lesson.