Page 31 - Start Up Mathematics_3

Rule 3: When a smaller symbol is written before a Mental Maths
larger one, then the value of the smaller symbol

is subtracted from the value of the larger symbol. Write the time shown in the
clock.
For example, IV = 5 – 1 = 4, IX = 10 – 1 = 9
XII
XI I
Rule 4: When three or more symbols are written X II
together in such a way that a smaller symbol lies IX III
between two greater symbols, then we subtract VIII VII VI V IV
the smaller symbol from the greater symbol placed
after it. ` :

For example, XIV = 10 + (5 – 1) = 10 + 4 = 14,
XIX = 10 + (10 – 1) = 10 + 9 = 19, XXIV = 10 + 10 + (5 – 1) = 20 + 4 = 24,

XXXIX = 10 + 10 + 10 + (10 – 1) = 30 + 9 = 39

Roman Numerals up to 39

Hindu- Roman Hindu- Roman Hindu- Roman Hindu- Roman
Arabic Arabic Arabic Arabic

1 I 11 XI 21 XXI 31 XXXI

2 II 12 XII 22 XXII 32 XXXII

3 III 13 XIII 23 XXIII 33 XXXIII

4 IV 14 XIV 24 XXIV 34 XXXIV

5 V 15 XV 25 XXV 35 XXXV

6 VI 16 XVI 26 XXVI 36 XXXVI

7 VII 17 XVII 27 XXVII 37 XXXVII

8 VIII 18 XVIII 28 XXVIII 38 XXXVIII

9 IX 19 XIX 29 XXIX 39 XXXIX

10 X 20 XX 30 XXX

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