Illustrative Mathematics K–5 · Grade 4 · Unit 4 · From Hundredths to Hundred-thousands
Welcome to the Rocket Lab! Read the fuel gauge, launch along number lines, punch in big numbers, fire the ten-times thrusters, round orbits, and add and subtract on the launch pad. Then fuel up for the Countdown. Each station matches lessons from class.
Each station deals 8 fresh problems (the Countdown deals 10). A right answer on the first try earns 10 points. After a wrong answer, the game names the likely mistake and gives one more try for 5 points. At the Countdown, each right answer fills one of the rocket’s 10 fuel cells.
Hints use the pictures from class: hundred grids, number lines in tenths and hundredths, place-value charts, number lines for rounding, and the standard algorithm worked column by column. A used hint caps that problem at 5 points.
Writing hundredths as tenths, thinking a decimal with more digits is bigger, leaving out the zeros that hold empty places, adding 10 instead of multiplying by 10, rounding the wrong way or to the wrong place, comparing first digits when the numbers have different lengths, forgetting to carry, and taking the smaller digit from the bigger one instead of trading.
Decimals stay in tenths and hundredths, in money and measurement. Whole numbers stay within 1,000,000 with few nonzero digits, and each addition or subtraction needs at most one trade (a trade across zeros counts as one, as in Lesson 21). Typed answers can use commas.
Each station matches a chapter of the Learn page for this unit, which walks through the ideas step by step.
Bees are Buzzing (Lesson 23) is an optional lesson, so there is no station for it.