Multiply with decimals Standard UW.GAP.5.M.NBT.07 Add, subtract, multiply, and divide decimals to hundredths using concrete models or drawing and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.
Essential Questions 1. What is addition? How do you add decimals? 2. What is subtraction? How do you subtract decimals? 3. What is multiplication? How do you use a model and partial products to represent multiplying decimals? 4. What is division? How do you use a model and partial products to represent dividing decimals?
Set.... Think about the strategies we use to multiply whole numbers.... Take turns with your face partner and describe how we multiply and divide whole numbers.
Objective: I can multiply decimals to hundredths place.
Let’s Review Decimal - a number with a fraction of tenths, hundredths, etc. written after a decimal point. Decimal point - the (.) between a whole number and fractions of tenths, hundredths, thousandths, etc. Digit- any of the numerals 0-9, which may be part of a larger number. 24.56 x 4 . 1 = 100.696
Think back to Adding and Subtracting Decimals Step 1- line up the decimals Step 2- add any place holding zeros Step 3 - add or subtract like you always do Step 4 - bring the decimal straight down Multiplication is much different, let’s learn how...
Rules for Multiplying Decimals When multiplying decimals, multiply just like normal then move decimal over to the right, then move decimal that many place in answer to the left.
Multiplying Decimals Example 1 Solve = 10.7 x 0.13 10.7 1 decimal place
Multiplying Decimals Example 1 Solve = 10.7 x 0.13 10.7 x0.13 1 decimal place 2 decimal places
Multiplying Decimals Example 1 Solve = 10.7 x 0.13 10.7 x0.13 321 1 decimal place 2 decimal places
Multiplying Decimals Example 1 Solve = 10.7 x 0.13 10.7 x0.13 321 1070 1 decimal place 2 decimal places
Multiplying Decimals Example 1 Solve = 10.7 x 0.13 10.7 x0.13 321 +1070 1.391 1 decimal place 2 decimal places 3 decimal places
Let’s watch how to multiply with models
Let’s try one together... 4.56 x .83
Now you try 16.73 x 4.89
Closure Think about what is different about multiplying whole numbers and multiplying decimals Repeat todays objective
Independent Practice 1. 45.2 x 2.3= 2. 98.01 x 7= 3. 6.6 x 4.9