Test
Finding the Unknown Factor, Dividend and Divisor
This test develops finding an unknown factor, dividend or divisor by using inverse operations. Students choose the correct inverse operation, form a valid equation and check the value obtained for the unknown.
Time left: 00:00:00
Sample questions
- Find the number that should replace the question marks.
- ___ × ? = ___. Find the unknown factor.
- ÷ ___ = ___. Find the unknown dividend.
- One box holds ___ balls. There are ___ balls altogether. How many boxes are filled?
- ___ sweets are given out with ___ to each child. How many children receive sweets?
Finding an unknown factor, dividend or divisor
Multiplication and division are inverse operations, so one can be used to solve or check the other. In 7 × x = 42, the unknown factor is found by dividing the product by the known factor: x = 42 ÷ 7 = 6.
Main rules
- Unknown factor = product ÷ known factor.
- Unknown dividend = divisor × quotient.
- Unknown divisor = dividend ÷ quotient.
In x ÷ 5 = 8, the unknown dividend is 5 × 8 = 40. In 48 ÷ x = 6, the unknown divisor is 48 ÷ 6 = 8. Substitute the value into the original equation and check that both sides are equal.
A common mistake is to perform the same operation for every division equation. First identify which component is unknown and then select the corresponding rule.
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