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Worksheet Grade 4 Math

Juniper Dam Test Tank: Adding and Subtracting Fractions

A grade 4 worksheet at the fictional Juniper Dam where students add and subtract fourths and eighths, including mixed numbers, to track a test tank and lake level.

Objectives

  1. Students will add and subtract fractions with like denominators referring to the same whole.
  2. Students will add and subtract mixed numbers with like denominators in a water context.

Vocabulary

Key words: fraction, mixed number, fourth, eighth

Teacher overview

The fictional Juniper Dam holds back a lake, and a small test tank at the dam is filled and drained during checks. This worksheet uses the tank and the lake level to practice adding and subtracting fractions with like denominators, including mixed numbers, which is the heart of 4.NF.B.3. All fractions in one problem share the same bottom number, so students add or subtract only the top numbers. A common error is adding the bottom numbers too; watch for a student who writes 1/4 + 2/4 as 3/8 instead of 3/4.

Juniper Dam Test Tank: Adding and Subtracting Fractions — Grade 4 Math
Name: ____________________________ Date: ______________

Student Worksheet

The test tank at Juniper Dam is marked in fourths. The lake level is measured in eighths of a foot. Answer each item. Keep the bottom number the same when you add or subtract.

  1. The tank is 1/4 full. You add 2/4 more. How much is in the tank now?
  2. The tank is 3/4 full. You drain 1/4. How much is left?
  3. Add 2/4 and 3/4. Write the answer as a mixed number.
  4. On Monday the lake rose 3/8 foot. On Tuesday it rose 2/8 foot. How much did it rise in all?
  5. The lake fell 5/8 foot, then fell 1/8 foot more. How much did it fall in all?
  6. A gate log shows 1 1/4 hours, then 2 1/4 hours. Add the two times.
  7. Subtract 1 1/4 from 3 3/4.
  8. The tank was full at 4/4. You drain 1/4. How much is left?
  9. Two days of rain gave 4/8 inch and 4/8 inch. How much fell in all? Write it as a whole number.
  10. Tell why 2/4 and 1/2 show the same amount. Use words.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: 3/4 tank. Add the top numbers only: 1/4 + 2/4 = 3/4.
  2. Answer: 2/4 tank. Subtract the top numbers: 3/4 − 1/4 = 2/4, which also equals 1/2.
  3. Answer: 1 1/4. 2/4 + 3/4 = 5/4, and 5/4 is one whole and 1/4, written 1 1/4.
  4. Answer: 5/8 foot. 3/8 + 2/8 = 5/8.
  5. Answer: 6/8 foot. 5/8 + 1/8 = 6/8, which also equals 3/4.
  6. Answer: 3 2/4 hours. Add whole numbers and fourths: 1 + 2 = 3 and 1/4 + 1/4 = 2/4, so 3 2/4, or 3 1/2.
  7. Answer: 2 2/4. 3 3/4 − 1 1/4: 3 − 1 = 2 and 3/4 − 1/4 = 2/4, so 2 2/4, or 2 1/2.
  8. Answer: 3/4 tank. 4/4 − 1/4 = 3/4.
  9. Answer: 1 inch. 4/8 + 4/8 = 8/8, and 8/8 is one whole, so 1 inch.
  10. Answer: They are equal. 2/4 means two of four equal parts, which is half of the whole, and 1/2 is also half, so the two fractions name the same amount.

Differentiation

Support

Give students fraction strips folded into fourths and eighths so they can build each amount before adding or subtracting. Model item 1 by laying 1/4 next to 2/4 and counting three fourths. Circle the bottom number in each problem to remind students it stays the same.

Extension

Ask students to write a two-step tank story of their own that ends at exactly 3/4 full, using at least one add step and one subtract step, then show the number sentence that proves it.

ELL supports

Label a fraction strip with the words "one fourth," "two fourths," and so on, in English and, where possible, the student's home language. Provide a sentence frame for item 10: "2/4 and 1/2 are equal because both show ___ of the whole."