Complete the Subtraction Sentence
π΅οΈββοΈ Missing suspects! In a subtraction problem, doing the "opposite math" rule depends entirely on which piece is missing!
Do this: Read the concept below, then try the quiz or activity.
Concept
Subtraction algebra is the trickiest math on the test. You have to look at the blank space very carefully.
π― Rule 1: The START is Missing ____ - 250 = 400 * If the giant starting number is missing... do the OPPOSITE math! Add the pieces back together! * 400 + 250 = 650. (Start number found!).
π― Rule 2: The MIDDLE is Missing 800 - ____ = 500 * If the piece being taken away is missing, DO NOT ADD! (800 + 500 = 1300. Is 800 - 1300 = 500? No! That's impossible!). * Just SUBTRACT the answer from the Start! * 800 - 500 = 300. (The missing middle piece!).
Try it
Which rule do you use?
Instructions: Check the blank! Is the giant starting number missing? Or just a piece in the middle?
Problem 1: _____ - 150 = 300 * Start missing! Add them back together! * 300 + 150 = ___ * Answer: ___
Problem 2: 950 - _____ = 800 * Middle missing! Subtract the answer! * 950 - 800 = ___ * Answer: ___
Problem 3: 500 - _____ = 250 * Answer: ___
Problem 4: _____ - 418 = 100 * (Add them! But watch the dials!) * Answer: ___