[Chapter 5.2] Operations with Decimals: Line Up, Count Places, Slide the Point | Pre-Algebra

Tenths must combine with tenths, and a product of tenths is counted in hundredths. This calm, step-by-step explainer uses what decimals mean to decide where each point belongs. You'll see: • adding and subtracting by lining up the points • why lining up the points stacks like place values • multiplying, then counting decimal places • why the places add • multiplying and dividing by 10, 100, 1000 • dividing by sliding both points • eight worked examples The full lesson, with worked examples and practice: https://mathbyfirstprinciples.org/pre... 0:00 Welcome, and what you'll learn 1:20 Adding and subtracting: line up the points 2:14 Why lining up the points works 3:05 Worked Example 1: adding with a carry 3:47 Worked Example 2: subtracting with borrows 4:46 Multiplying: multiply, then count the places 5:23 Why the decimal places add up 6:05 Worked Example 3: a two-place product 6:51 Worked Example 4: a zero that must stay 7:37 Multiplying and dividing by 10, 100, 1000 8:33 Dividing: make the divisor whole 9:07 Why sliding both points keeps the quotient 10:08 Worked Example 5: one move 10:33 Worked Example 6: two moves 11:14 Worked Example 7: the answer need not be whole 12:03 Worked Example 8: a whole divisor 13:01 Key takeaways Narration is voiced with text-to-speech. Also available in Spanish, Hinglish, and Mandarin. #math #prealgebra