Verbal nouns are similar to verbal adjectives, in that they are constructed from phrases. But as the name suggests, verbal nouns turn phrases into nouns.
A verbal noun is made from a phrase by replacing the verb with past/present tense stem + அது
See the lesson on Class 5 Verbs for reference on Class 5 future tense stems.
Another way of thinking about verbal nouns is this: replace the verb suffix (for nouns besides அது and அவை) with -அது. For அது and அவை in the past and present tense, also replace the verb suffix with -அது.
Verbal nouns can take case suffixes. When taking case suffixes, verbal nouns behave like அது. The final -அது will be replaced with whatever word அது would change to in the same situation. For example, -அது would change to -அதனால் in the instrumental case, and அதற்கு in the dative case.
Fill in the sentences with an explanation or description using a past action. s
Ex: குடும்பம் அடுத்த மாதத்தில் ஏழு நாள் பயணம் ___ திட்டம் போன மாதம் போட்டார்கள். (செய்1a, -உக்காக)