Illustrative Mathematics
Reasoning about Multiplication and Division and Place Value, Part 2
The learner puts reasoning and estimation to work. The directions are to place a decimal in the answer to make the equation true. Pupils are to look at the two problems, one multiplication and one division, and estimate an answer. No...
EngageNY
Fraction Multiplication and the Products of Decimals
Class members come up with a hypothesis on the number of decimal digits in the product of two decimals. Learners work in groups to complete several decimal multiplication problems. The results help groups develop a conjecture on the...
Illustrative Mathematics
Placing a Square Root on the Number Line
There are many ways to approach finding the rational approximation of an unknown square root. Here is a problem that will help math learners make a connection between square roots and their order on a number line. As usual, determine two...
EngageNY
The Division Algorithm—Converting Decimal Division into Whole Number Division Using Fractions
Knowing the standard algorithm opens up a whole new world of division. Scholars learn how to convert division involving decimals to division involving whole numbers to use the standard algorithm. Knowing how to multiply with powers of...
West Contra Costa Unified School District
The Power of Ten: Building a Magnitude Model
Add visual representation to teaching place value with a magnitude model. Using adding machine tape, pupils build a linear place value strip from 1 to 100.