Grade 4 Lesson 3 11 OPEN SENTENCES Math

Grade 4 Lesson 3. 11 OPEN SENTENCES

Math Message Is this sentence true or false? The sum of 10 and some number is fifteen. Explain your answer in your ISN. Can you write this sentence using math symbols? 10+ x = 15 Where x represents some number or the missing number.

Algebraic Thinking Any letter can be used to represent numbers that are missing. A letter or symbol that is used to represent a missing number is called a VARIABLE. What number could x represent that would make our statement true? 5…. 5 could represent the number because 10+5=15 A sentence that has a variable in it, such as 10+x=15 is called an OPEN SENTENCE. To solve an open sentence, replace the variable with the number that makes the sentence true. The number that makes the sentence true is called the SOLUTION.

Finding Solutions to open sentences 12 + x = 55 12 + 43 = 55 36/ p = 9 36/4 = 9 17 = z – 8 17 = 25 – 8 2 * x = 18 2 * 9 = 18 k/ 6 = 10 60/ 6 = 10 21 – 8 = n m/25 = 4 100/ 25 = 4 21 – 8 = 13 Challenge: Get a calculator…. . Solve the following open sentence without using the minus key! (Pretend it’s broken!) 452 + x = 735

Try these with a broken calculator! Open Sentence Broken Key Solution 75 + x = 415 - Y + 128 = 563 - R – 156 – 954 + P/34 = 27 x y/29=52 x 19 * t = 1, 330 If you were able to complete these, do page 74 in your workbook. If you had trouble, please do page 73 first (and ask your teacher for help!) /

Egypt Map Scale Measure the distances between locations on a map of Egypt. Us the map scale to convert the measurements to actual distances. This is page 75 in your workbook.

Homework page for this lesson is page 99.

Enrichment For enrichment, please complete page 101. Determine the unknown values of letters in animal names.