Roman numerals have no Common Core standard of their own, so this worksheet is keyed to 4. NBT. B. 4, fluently adding and subtracting multi-digit whole numbers, because building a Roman numeral past 20 is exactly that: combining L (50) and C (100) with X, V, and I using addition, and using subtraction whenever a smaller numeral sits in front of a bigger one. A fourth grader who already knows I, V, and X from Grade 3 now meets two new letters and a wider subtractive rule: X can be placed before L or C to subtract, the same way I is placed before V or X, so XL is 40 and XC is 90. This worksheet keeps that rule in front of the child instead of hiding it behind bare conversions.
Some questions convert between a numeral and a number up to 100. Others ask directly why a pair like XL and LX, which share the same two letters, land on 40 and 60. A few show a common wrong form, like XXXX for 40 or LXXXX for 90, and ask for the correct numeral, because seeing why four X's in a row is not allowed reinforces the repeat-at-most-three rule from Grade 3. Real examples, such as Henry VIII and a stadium section numbered LXXV, show these numerals still appear outside a math book. Encourage your child to write out the value of every letter before combining them, largest to smallest.
What your child will learn
Convert Roman numerals with I, V, X, L, and C to numbers up to 100
Convert numbers up to 100 to Roman numerals
Explain subtractive pairs such as IX, XL, and XC
Explain which small numerals may subtract from which large ones
Spot and correct an incorrectly written Roman numeral
Worked example
XL places X before L, so 10 is subtracted from 50, making 40. LX places X after L, so 10 is added to 50, making 60.
Common mistake
Writing 40 as XXXX or 90 as LXXXX instead of using the subtractive forms XL and XC.
Helpful hint
Work from the largest value down: hundreds (C), fifties (L), tens (X), fives (V), ones (I).
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